Journal of Mason and Dixon

INTRODUCTION

I. THE MANUSCRIPT JOURNAL

The manuscript Journal is now in the National
Archives, Washington, D. C., where it is in Record
Group 59, General Records of the Department of
State.

The following description is largely taken from an
account prepared by the Department of State, with
additional comment by the present editor. The
volume is labeled on its backstrip as follows: “Mason
& / Dixon’s / Line. / Original / Journal / of the
/ Commissioners. / 1763.”

The volume ... is labeled on its backstrip as follows:
“Mason & / Dixon’s / Line. / Original / Journal / of
the / Commissioners. / 1763.”

The entries were probably made in a blank book with
heavy paper covers, which are bound into the present vol¬
ume. Later the leaves and covers of the blank book were
cut apart and were glued to the “stubs” of a binder, to which
various letters received were attached in the same manner.
The manuscript was little damaged by these changes, though
part of a word, is occasionally concealed at the end of a line
where the stub overlaps a sheet.

The journal is in a single hand throughout and is signed
at the end “C: Mason.” Most entries are in the first person
plural, referring to the joint activities of Mason and Dixon;
but others are in the first person singular, referring to
events that occurred when Dixon was absent. From these
facts it seems clear that the journalist is Mason. Slight vari¬
ations in color of ink and slant of handwriting from one
entry to another indicate that the journal is the original
document, written from day to day, and not a smooth copy,
prepared at a later time.

At the front of the volume, probably inserted when it
was rebound by the Department of State, are copies of
correspondence between the Secretary of State and George
W. Childs, of Philadelphia, November 2, 1876-March 8,
1877, relating to the purchase of the journal by the United
States Government from Judge Alexander Janies, of the
Supreme Court of Nova Scotia. These copies are followed
by several leaves of scattered notes, dated September 17,

1762; August 19-21, 1763; December 19-22 and 27-31, 1763;
January 1-2, 1764; and April 1767. Bound at various points
in the journal, in order of mention, are original letters re¬
ceived by Mason and Dixon from Richard Peters (Phila¬
delphia, January 7, 1764), C. Morton (September 1, 1766),
Hugh Hamersley (London, March 22, 1766), William
Allen, Benjamin Chew, and John Ewing (Philadelphia,
September 19, 1766), Thomas Penn (London, June 17,
1767), Nevil Maskdyne (Greenwich, February 24, 1767),
Horatio Sharpe and others (Chester) June 18, 1767), Ben¬
jamin Chew (Philadelphia, December 10, 1767), Thomas
Penn (London, June 17, 1767), Charles Thomson (April
15, 1768), and Thomas Penn (near Windsor [England],
November 14, 1768).

A fair copy of the Journal in the same hand, that of
Mason, is deposited in the Hall of Records of the State
of Maryland, Annapolis.

An abridged copy of the Journal was printed under the
title of “Field Notes and Astronomical Observations of
Charles Mason and Jeremiah Dixon,” in Report of the
Secretary of Internal Affairs of the Commonwealth of
Pennsylvania, Containing Reports of the Surveys and Re-
Surveys of the Boundary Lines of the Commonwealth, Ac¬
companied with Maps of the Same (Harrisburg, 1887),
pp. 59-281.

The text of the Journal was reproduced by offset
lithography directly from a typewritten transcript
made under the editor’s supervision. Brief explana¬
tory statements added by the editor are introduced by
the words “Editorial comment” or are enclosed in
parentheses. Such parenthetical passages should be
readily distinguishable from those appearing in the
original document. Some abbreviations, as “do” for
“ditto” and “So” for “South,” have been spelled out.
A few geographical and other terms have been mod¬
ernized. A few abbreviated first names have been
spelled out.

HISTORICAL PRELUDE TO THE SURVEY OF MASON AND DIXON

The background of the boundary controversy which
waged between Pennsylvania and Maryland from
1681 to 1763 was of great scope and embraced numer¬
ous tedious considerations. Chief among these were
questions of title resulting from exploration or con¬
quest, interpretation of inadequate maps, and errors,
ambiguities, and mathematical impossibilities in geo¬
graphic delineation. Furthermore, the entire problem
was badly complicated by the careless practice of En¬
glish monarchs in making grants of land which had
already been chartered by their predecessors. In addi¬
tion to such well-founded difficulties, one can perceive
throughout the entire contest a partisan desire to
evade numerous clearly outlined specifications of the
grants.

In consequence of the voyages of the Cabots in 1496-
1497, England claimed by international law all of the
Atlantic seaboard of North America from Nova Scotia
to Cape Fear in present North Carolina. On the basis
of such claims, King James I made the first two grants
to the London and Plymouth Companies which re¬
spectively settled Jamestown in 1607 and Plymouth in
1620. The northernmost limit of the London Com¬
pany in the third charter of 1611 was specified as the
forty-first parallel of north latitude, and the southern¬
most limit of the Plymouth Company in 1620 was to
be the thirty-eighth parallel. There was an obvious
overlap here which included more than half of present
Pennsylvania and New Jersey, all of Delaware and
Maryland, and much of present Virginia. However,
this overlap brought no controversy between James¬
town and Plymouth, as neither colony had early set¬
tlements within the area adversely assigned.

The colonization of Maryland may be traced to sev¬
eral events in the life of Sir George Calvert, subse¬
quently the first Lord Baltimore, who was appointed
to office in Ireland soon after the ascension to the
throne of James I. His demonstrated ability and char¬
acter gave rapid advancement to a position of influ¬
ence and gained for him the esteem of the King. He
was appointed Secretary of State in 1618 and was ele¬
vated to the peerage in 1625.

George Calvert’s first attempt in establishing a col¬
ony was in Newfoundland in 1623, but he became
discouraged in the undertaking on account of the
severity of the climate and accordingly abandoned the
project. For over a decade he had been a member of
the Virginia Company of Planters which was inter¬
ested in the settlement at Jamestown. When Virginia
became a Royal Province in 1624, he was made a
member of the provincial council in England. Still

interested in colonization in the New World, he made
a trip to Virginia and on his return petitioned King
Charles I for a grant of land in that colony. At first
George, Lord Baltimore, 1 requested territory south of
the James River, but opposition was interposed and
he subsequently requested and was granted land in
northern Virginia. According to his charter, which did
not pass the Great Seal until June 20, 1632, the colo¬
nial territory of Maryland was to be bounded on the
north by the fortieth parallel of north latitude, on the
south by the south bank of the Potomac River and by
a parallel of latitude through Watkins Point on the
Eastern Shore, on the east by the Atlantic Ocean, and
on the west by a meridian through the source of the
Potomac River. The charter specifically precluded the
settlement of territory previously cultivated, i.e.,
“hactenus inculta.” George, Lord Baltimore, died in
England on April 15, 1632, before the granting of the
charter. However, its provisions were awarded to his
heir, Cecil, second Lord Baltimore, who in turn en¬
trusted to his brother, Leonard Calvert, the carrying
out of the initial details of colonization. He, with a
company of about three hundred settlers, arrived on
the lower Potomac on March 27, 1634, and established
the first settlement in Maryland at St. Mary’s City.
The Calverts were Catholics at that time and the
founding of Maryland was principally intended to
provide a refuge in the New World for members of
that faith who in England were without political or
civil rights. However, as few Catholics came and as
there was no discrimination against non-Catholics, the
former soon numbered less than one-fourth of the
colony.

As was earlier pointed out, the charter of Maryland
provided for the colonization of land hitherto uncul¬
tivated. Settlements were thus prohibited where others

1 The title of Lord Baltimore extends over a period of one
hundred and forty-seven years, i.e., from 1624 to 1771. George
Calvert, first Baron of Baltimore, was raised to the peerage by
Charles I, and the title passed from father to son until it reached
Frederick Calvert, sixth Lord Baltimore, who died in Naples in
1771 without an heir. It is so frequently used without specifying
the individual that much confusion has resulted. In order to pre¬
serve clarity in this account, the names and dates of each are
given below. The first year in each case is the date of accession,
and the second is the date of death.

First Lord Baltimore: George Calvert, 1624-1632

Second Lord Baltimore: Cecil Calvert, 1632-1675

Third Lord Baltimore: Charles Calvert, 1675-1715

Fourth Lord Baltimore: Benedict Leonard Calvert, 1715-1715

Fifth Lord Baltimore: Charles Calvert, 1715-1751

Sixth Lord Baltimore: Frederick Calvert, 1751-1771

2

HISTORICAL PRELUDE TO THE SURVEY

3

already were in possession. This gave rise to a minor
territorial controversy with Virginia, which had ear¬
lier established outposts on Kent Island opposite An¬
napolis and Palmer’s Island near Havre de Grace.
Otherwise, no Maryland territory was settled by
Caucasians at the time of the founding of Saint Mary’s
City in 1634.

Soon after the advent of the seventeenth century,
Holland was anxious to establish a foothold in North
America and needed some pretext to challenge the
English claim of discovery. In great dynastic move¬
ments, adversaries usually attempt to interpret inter¬
national law in their own behalf. In this instance it
was argued that John Cabot had not touched suffi¬
ciently close to the North American mainland in the
area of their interest to consider it an English posses¬
sion. The Dutch claim was that the explorations of
Henry Hudson in 1609 were more detailed, that he
had carefully navigated the South (Delaware) River
and North (Hudson) River, and that this geographi¬
cal research transcended that of Cabot and was a basis
for a better title. However, a study of the contempo¬
rary maps of this area revealed that both the Delaware
and the Hudson Rivers were not unknown to ex¬
plorers, and the British never admitted the validity of
the .Dutch*title on the basis of discovery.

In conflict with English claims, the Dutch estab¬
lished a settlement in April, 1631, at a place variously
denominated Swaanendael, Hoornkill, and Whorekill
on the present Lewis Creek in Sussex County, Dela¬
ware. The attempt was unsuccessful, as the colony was
destroyed by an Indian massacre the following year.
This failure was followed by a second Dutch attempt
in 1632 to which opposition was registered by the Vir¬
ginians when the Governor (DeVries) visited James¬
town prior to proceeding up the Delaware. Although
the good will of the Indians was gained, the settle¬
ment was abandoned the same year after failure of
efforts at fishing and whaling.

Sweden became interested in colonial expansion at
this time but, as with Holland, the question of legal
title to territory on the Atlantic seaboard had to be
faced. This dilemma they attempted to resolve by the
device of purchasing territory from the natives. They
planted a settlement at Paradise Point near Dover in
March, 1638, in territory which earlier had been as¬
signed by Charles I to Maryland. About two centuries
later Chief Justice Marshall ruled that the predatory
claims of discovery of land of natives (Indians) pre¬
empted the claims to title by purchase.

The Dutch were still entrenched on Manhattan and
considered spurious the Swedish title of purchase from
natives of land along the Delaware. In 1651 they in¬
vaded the Swedish settlement and erected Fort Casi-
mir, the present New Castle. Three years later the
Swedes retaliated and recaptured their stronghold.
This somewhat bellicose proceeding was concluded
two years later when the Dutch again invaded and

recaptured Fort Casimir. The Swedes who remained
in the contested territory eventually allied themselves
with the English or Dutch.

By 1659 Cecil, second Lord Baltimore, found his
charter rights very firmly challenged by the Hollanders,
who were now uncontested in their settlement along
the Delaware. Each side was soon making representa¬
tions to the other claiming infringement of territory.
The matter was referred by the Dutch to Governor
Stuyvesant in Manhattan, while Lord Baltimore peti¬
tioned King Charles II for a confirmation of his char¬
ter which was granted in 1661. Matters had now
reached an impasse. Not only was Maryland being
populated by a hostile foreign power but northern
and southern English colonies were severed by the
Dutch stronghold on Manhattan and contiguous set¬
tlements. England became convinced that the Dutch
must be dislodged.

In 1664 Charles II granted to his brother Janies,
Duke of York, all the land between the Connecticut
and Delaware Rivers. Acting as Lord High Admiral,
he immediately launched a naval attack on Fort Am¬
sterdam, which capitulated on September 8. 1664. Al¬
though the west side of Delaware Bay was not con¬
veyed to the Duke of York, he, nevertheless, late in the
same month appeared with his fleet before the Dutch
settlement at New Amstel in Lord Baltimore’s terri¬
tory and reduced it to submission. After a brief success
at re-conquest during disturbances in England in
1673, Holland finally ceded to the British in 1674 all
of her possessions in North America. The theory had
been held by the English that the Dutch never legally
possessed land in North America, and on this assump¬
tion they could not surrender to the Duke of York
what they did not actually possess. Therefore it would
appear that Lord Baltimore should now have been in
uncontested possession of his territory adjacent to the
west side of Delaware Bay.

William Penn I had been a distinguished admiral
in the British Navy and the family was highly es¬
teemed by King Charles II and his brother James.
Duke of York. He had loaned the King 16,000 pounds
sterling. Young William Penn II had embraced the
Quaker faith and desired to found in the New World
a colony primarily for this religious sect. In lieu of the
personal debt of the King to his father, he persuaded
Charles II to grant him a charter to territory in the
New World between Maryland and New York. This
document was signed by the King on March 4, 1681.
More specifically, the northern boundary of Pennsyl¬
vania was designated as the forty-third parallel of
north latitude, and the western boundary as a merid¬
ian five degrees west of Delaware Bay. The southern
boundary was more complex but was to extend east¬
ward along the fortieth parallel of north latitude
until it intersected a circle of twelve miles radius cen¬
tered at some unspecified point in the settlement at
New Castle, and the arc of the circle was to be the

4

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

boundary from the point of intersection to Delaware
Bay. This body of water was to be the eastern
boundary. The carelessness with which such matters
were handled in England will be obvious if one will
take a map, draw a circle of twelve miles radius
around New Castle courthouse, and observe that the
fortieth parallel of north latitude passes about thir¬
teen miles north of such a circle. Thus it is seen that
the charter of Pennsylvania did not designate a closed
figure. At this time began the boundary controversy
between the Penns and the Calverts which was des¬
tined to persist for eighty-two years.

Charles, third Lord Baltimore, was in Maryland at
the time of the granting of Penn’s charter. He received
notice thereof on April 2, 1681, and he was advised to
confer with William Penn II to establish the bound¬
aries between their two provinces. By letter from the
King, they were required

to make a true division and separation of the said provinces
of Maryland and Pennsylvania, according to the bounds and
degrees of our said Letters Patent and fixing certain Land
Marks where they shall appear to border upon each other
for the preventing and avoiding all doubts and controversies
that may otherwise happen concerning the same.

William Penn had selected a kinsman, William
Markham, to act as deputy governor for him. He
visited the third Lord Baltimore at the latter’s home
on the Patuxent River in August, 1681, but became ill
and was cared for by his lordship for three weeks.
Following his recovery, it was not considered that
an unbiased conference could be held and they ad¬
journed to meet again the following October. Other
postponements took place on account of illness and
difficulties of transportation, and negotiations were
broken off for several months. During this interim,
influential citizens in the northeastern counties of
Maryland received letters from William Penn declar¬
ing that they were settled in Pennsylvania and that
their tax payments to Maryland should discontinue.
This led to bad relations in the area concerned. Ob¬
servations for latitude were taken at several points on
Delaware Bay between the present sites of New Castle
and Chester and all seemed to indicate a value sub¬
stantially under forty degrees. Finally in a conference
between the second Lord Baltimore and Governor
Markham near the present site of Chester, the former
suggested that the two go up the Delaware River to
the fortieth parallel. This was opposed by Governor
Markham on the ground that William Penn’s charter
specified that his lower boundary should be no more
than twelve miles north of New Castle. He further¬
more asserted that, if the two patents overlapped, the
matter would have to be resolved by the King. During
this visit the third Lord Baltimore ordered the inhab¬
itants of the surrounding area to pay no further taxes
to Penn and stated that he would return later to col¬
lect his own.

At this time the third Lord Baltimore’s title to the

section later named the “Three Lower Counties” or
the present State of Delaware began to be questioned.
He had exercised considerable effort to establish set¬
tlements in this area but colonization proceeded slowly.
When the Duke of York conquered the Dutch, he was
actually left in possession of this territory, which he soon
assigned to William Penn. It could hardly have es¬
caped the attention of the Privy Council in England
that such a situation would create further boundary
complications, but as the Duke soon would ascend to
the throne as King James II, it did not appear pru¬
dent to oppose him.

Previous negotiations between the third Lord Balti¬
more and Governor Markham had been attended
with much hostility, and it seemed desirable to await
the arrival of William Penn before considering fur¬
ther conferences. He arrived at New Castle on Octo¬
ber 24, 1682, and took possession of the main body of
his estate and also of the territory recently assigned to
him by the Duke of York. Immediately he took steps
to amalgamate the two areas.

This union having been accomplished, William
Penn proceeded to southern Maryland, where in Anne
Arundel County near Annapolis he conferred with
Lord Baltimore on December 13, 1682. Here various
impractical and unscientific procedures were proposed
by Penn, some at the recommendation of the King, for
locating the southern boundary of Pennsylvania, i.e.,
forty degrees north latitude. One method suggested
was to measure northward from Cape Charles, Vir¬
ginia, which was thought to be at the latitude of
37°05', a figure now known to be only 1.5 minutes too
small. Sixty statute miles was proposed as the mea¬
sure of a degree, whereas actually in this zone 69.5
statute miles is much closer to the truth. Moreover, a
route survey cannot be run very far north from Cape
Charles without entering the Chesapeake Bay, as the
Virginia portion of the Delmarva Peninsula runs
northeasterly. Lord Baltimore’s alternative suggestion
that they go up the Delaware River with a sextant
and locate the fortieth parallel of north latitude
would have been much more practical.

It is believed that Penn knew from earlier recon¬
naissance that the fortieth parallel would lie above
navigation on the Chesapeake. By using the measure
of 60 miles per degree as the King recommended, he
would have been able to gain about 28.5 miles in the
measurement of about three degrees northward from
Cape Charles. This would have assured him a port on
the headwaters of the Bay. Of course, there most surely
were able scientists in England at this period, partic¬
ularly Newton, who knew the dimensions of the earth
sufficiently well to advise the King of the approximate
measure of a degree of latitude in statute miles much
more precisely than the figure he proposed. One sees
here a lack of perseverance and thoroughness.

Charles, Lord Baltimore, questioned Penn at this
conference regarding the transfer of the “Three Lower

HISTORICAL PRELUDE TO THE SURVEY

5

Counties” to the latter by the Duke of York. Penn
stated that he would discuss this point as soon as the
location of the northern boundary of Maryland was
fixed. The following morning Lord Baltimore es¬
corted William Penn to a Quaker settlement near
Galesville, Maryland, about twelve miles south of
Annapolis. After a meeting with the Quakers, Penn
returned home by the Eastern Shore. Thus ended the
first negotiations between William Penn and the third
Lord Baltimore. Each proprietor had outlined his
position, but no progress was made in adjusting their
differences.

The following April, 1683, Penn communicated
with Lord Baltimore and requested him to specify a
place and time for a further discussion of their
boundary issue. Arrangements were concluded for
them to confer at New Castle later in the same month.
The agenda included further discussion of the im¬
practical procedure of making a linear measurement
northward up the present Delmarva Peninsula, but
the third Lord Baltimore disagreed with this and
stated that all they needed was a latitude observation
near the fortieth parallel. At this time Penn agreed to
have the boundary established at Lord Baltimore’s
charter position if the latter would sell sufficient land
adjacent to the headwaters of the Chesapeake Bay to
insure his colony the access of incoming ships from
England. But his lordship declined this proposal. The
conference concluded without constructive results.

In 1682 two incidents occurred which may fife
evaluated as contributing heavily to the loss of the
cause of Maryland. When Charles, third Lord Balti¬
more, returned from England after receiving his title,
he was accompanied by his cousin, Colonel George
Talbot. The latter appears to have been a man of
much ability, destined to rise to a position of great
prominence. He was granted an immense acreage near
the headwaters of the Chesapeake Bay, probably to
constitute a buffer area to fend off the migration of
settlers from the territory over which Penn exercised
dominion.

A sufficient number of astronomical observations
had been made along the lower Susquehanna for the
latitude to be fairly well established. Nevertheless, in
the summer of 1682 Colonel Talbot ran a survey line
from the mouth of Octoraro Creek in latitude 39° 39'
to the mouth of Naaman Creek, latitude 39°48', on
the Delaware River about twelve miles northeast of
New Castle. The length of this line was about forty-
two miles and was run on a true bearing of about
N73°E. On the average it was nineteen miles below
the charter boundary of Maryland. This appears to
have been a rough survey. No monuments were
erected but some trees were blazed. Charles, Lord
Baltimore, described this line as being “east-west” but
too far south to his “disadvantage.” However, one is
constrained to inquire how an error of seventeen de¬
grees in azimuth could have been made, as no such

magnetic variation is believed to have existed during
the last several centuries in that region. This line im¬
mediately became the cause of much trouble. Penn
maintained that Charles, Lord Baltimore, considered
it the northern boundary of Maryland. Althbugh
there is little doubt that this view was taken by many
Marylanders, there is ample documentation that it
was not shared by the proprietor. The diplomacy was
further complicated by a somewhat bizarre proceeding
in late 1683 wherein the intrepid Colonel Talbot
presented himself at Penn’s residence on the Schuylkill
River and demanded that the latter surrender to Lord
Baltimore “all the Land upon the West Side of Dela¬
ware River and Bay, and the Seaboard side of fourtieth
Degree of Northerly Latitude, and more particularly
all that part thereof which lyeth to the Southward of
the markt lyine aforesaid.” The stalwart proprietor of
Pennsylvania appears to have been somewhat hard put
by the audacity of the Maryland colonel. He gave a
lengthy reply in writing as to why he could not comply.
It is believed that these two incidents had their impact
in England, where in the inner circle of the King’s
Court William Penn already had superior standing.

The controversy now stood at a deadlock, and both
sides realized that their conflicting demands would
have to be referred to the Mother Country for
adjudication. Such an arbitration of their interests
was welcomed by Penn because of his high esteem in
England and was favored by the Duke of York, the
heir apparent to the throne. Conversely, the third
Lord Baltimore abhorred such a proceeding, as he had
been out of touch with the English court for many
years. Additional causes which weakened his case were
his action to obstruct the collection of the King’s taxes
in Maryland, the unfortunate incident of the Talbot
survey line,* and the demands of the impetuous Colo¬
nel Talbot on William Penn at his home. The case
was first referred to the King and Privy Council. The
King in turn referred it to the Board of Trade and
Foreign Plantations. With reference to the territory
along the Delaware, i.e., the “Three Lower Counties,”
Penn based his position on the claim that Lord Balti¬
more’s charter rights were preempted by the fact that
the Dutch and Swedes had settled that area prior to
the granting of the charter of Maryland. The decision
of the Board of Trade was that the present-day Del¬
marva Peninsula should be divided into two approx¬
imately equal portions north of Cape Henlopen and
that the eastern portion should be assigned to Penn.
The western portion would continue to be in Mary¬
land. In the matter of the northern boundary, this
appears to have been settled in favor of the third Lord
Baltimore—the fortieth parallel of north latitude pre¬
vailed. This was known as the Decree of 1685. How¬
ever, discussions concerning this issue continued and
ultimately the boundary was located about nineteen
miles below the charter parallel.

At the present time it is difficult to believe that

6

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

Charles I had intentionally inserted the cryptic Latin
phrase “hactenus inculta,” i.e., “hitherto unculti¬
vated,” specifically to give protection to the Dutch
and Swedes, none of whom were settled in present-day
Delaware at the time of the granting of the charter of
Maryland. However, during the course of the proceed¬
ing the Duke of York succeeded to the throne as King
James II. To have given a decision impugning the
King's integrity would have been tantamount to polit¬
ical ruin. Specifically, the difficulty was that the Duke
of York, now James II, had granted to William Penn
the “Three Lower Counties” to which he held title
only by conquest over the Dutch. Charles II had con¬
firmed the Maryland charter as late as 1661. But a
repetition at this time would have been to deny an
earlier title of the King’s—rather a sharp point. It is
apparent that the northern border now reaffixed as
forty degrees did not involve any act of James II.

If Lord Baltimore now had pressed for a survey, he
might have been able to save all the territory later lost
to Penn along his northern boundary. He surely had
the charter specification within his grasp at this time.
Nevertheless, there was dereliction in consummating
his award of the fortieth parallel in this decision of
1685. A good survey conducted in conformity with the
decree, and implemented with firm boundary markers
at frequent intervals, would have set a precedent diffi¬
cult to controvert. But he allowed his opportunity to
slip.

For many years following the decision of 1685, mat¬
ters were somewhat in a state of quiescence between
the two proprietors. William and Mary succeeded
James II in 1688. In 1690, because of what was consid¬
ered too independent a spirit in Maryland, the control
was taken from Lord Baltimore. The King assumed
jurisdiction at that time and it became a royal province
under a royal governor and remained in that status
until 1715. The same fate was shared by William
Penn, who lost control of his province in 1691, but his
influence in England brought a return of his domin¬
ions to him in 1694. Charles, third Lord Baltimore,
died in England in 1715, after an absence of thirty
years. He was succeeded by his son, Benedict Leonard
Calvert, fourth Lord Baltimore, who survived his fa¬
ther only a few months. Benedict was followed by his
son, Charles, fifth Lord Baltimore, to whom the pro¬
prietorship of Maryland was restored. William Penn,
who died in 1718, bequeathed his holdings in Penn¬
sylvania to his wife, Hannah Penn, who in turn trans¬
ferred her title to the province to her children, John,
Thomas, Richard, and Dennis equally. This maneuver
was inconsistent with the English law of inheritance
whereby one-half of the estate should have been con¬
veyed to William Penn, Jr., the founder’s eldest son
by an earlier marriage. The rapid changes in the
proprietorship of Maryland and the contested title to
Pennsylvania further contributed to set in abeyance
the boundary controversy. The period, however, was

not without one unsuccessful petition by Charles, fifth
Lord Baltimore, to Queen Anne in 1709 to set aside
the order of 1685 by which he had lost the “Three
Lower Counties” although his northern boundary had
been confirmed.

With the growth of population in the contested
areas, taxes were difficult or impossible to collect and
this meant loss of revenue to both proprietors. In 1731
Charles, fifth Lord Baltimore, petitioned King George
II for an order requiring the proprietor of Pennsyl¬
vania to join with him in the demarcation of the
boundaries. The matter was referred to the Commit¬
tee for Trade and Plantations. Lord Baltimore and
the Penns were present in England at the conferences.
Another round of innuendoes resulted, mostly over
the question of false geographical representations. But
ultimately agreement was reached in 1732 authorizing
the appointment of a commission to execute a bound¬
ary survey in accordance with terms in general deter¬
mined upon in 1685. This called for the equal division
of the Delmarva Peninsula from Cape Henlopen north¬
ward and for the northern boundary of Lord Balti¬
more’s dominions to be fifteen miles south of the City
of Philadelphia. The northern boundary of present
Delaware was to be a circle “drawn at twelve miles
distance” around the town of New Castle but the
precise location of the center was not specified. Com¬
missioners were ultimately appointed and their first
meeting was at New Castle on October 17, 1732. As
was usual, stalemates developed. The first concerned
what point in New Castle was to be adopted as the
center of the circle “at twelve miles distance.” The
only specification in the grant by Charles II to Penn
was that the center should be at some point within the
settlement of New Castle. The Pennsylvanians held
that the instruction to conduct the survey carried
within it the power to locate the center. The second
basis for argument was the dimension of the circle. It
is extremely doubtful that any mathematician or en¬
gineer would have thought of a circle “at twelve miles
distance” otherwise than as a circle of twelve miles
radius. The Marylanders disagreed as to the location
of the center and also insisted upon a circle of twelve
miles circumference (1.91 miles radius). Ultimately
the commissioners signed a joint note declaring that
they were unable to agree as to the basic instructions
to the surveyors for delineating the boundaries of
Pennsylvania. Maryland, and Delaware.

Border incidents had increased to the point that in
1738 the Governor and both houses of the Maryland
legislature petitioned King George II, imploring his
intercession. An edict was promptly forthcoming from
the King forbidding disorders in areas of controversy
and enjoining the proprietors from making grants
therein. The King ordered two temporary lines to be
run. One was to be 15.25 miles south of Philadelphia
on the east side of the Susquehanna and the other
14.75 miles south of Philadelphia on the west side of

HISTORICAL PRELUDE TO THE SURVEY

7

the same river. An attempt was made to run these two
lines under the supervision of both provinces, but the
Marylanders were absent when the survey was to
begin, and Penn hired two surveyors from New Jersey
to lay down the lines. Their work was accepted as the
boundary between Maryland and Pennsylvania until
1763.

The failure of the commissioners to proceed with
the boundary survey as outlined in the agreement of
1732 finally led to “The Great Chancery Suit” which
began in 1735. When the case was finally decided by
Lord Hardwicke in 1750, it was decreed that the
agreement of 1732 should be observed. Disputed
points were detailed, though incompletely: the center
of the circle should be the center of the town of New
Castle; the circle was to be of twelve miles radius and
the lower boundary of Delaware was specified as on a
parallel of latitude through Cape Henlopen as shown on
a map affixed to the Articles of Agreement.

Following the court’s decision, another attempt was
made to conduct a survey. Commissioners from Mary¬
land and Pennsylvania met at New Castle on Novem¬
ber 15, 1750, and decided upon the belfry of the
courthouse as the center of New Castle. But then a
controversy developed over the method of measuring
the radius of the circle. The Marylanders insisted
upon the distance being determined by chaining up
hills and down valleys. The Pennsylvanians favored
horizontal measure, which is the present legal method
of conducting a survey. The termini of radii located
by the former method obviously would not form a
circle. Further argument ensued as to the method to
be employed in locating additional points on the
circle. It appears that the Pennsylvanians suggested
the running of successive chords, each subtending one
degree at the courthouse belfry. The Marylanders
favored the running of radii centered at the belfry.
This latter method would have required more than
twelve hundred miles of linear chaining to locate each
degree point along the circle, and the Christiana River
would have had to be crossed over one hundred times.
The argument over the location of Cape Henlopen
had earlier been concluded by Lord Hardwicke and
pursuant thereto the local surveyors were dispatched
to that point and instructed to measure the length of
a parallel of latitude, or possibly the arc of a great
circle, across the Eastern Shore from the Atlantic to
the Chesapeake and to locate its mid-point. At a dis¬
tance of 66 miles from Cape Henlopen they came to
the shore of Slaughter Creek, an estuary of the Bay.
After chaining across the estuary and Taylor’s Island
(actually a peninsula separated from the mainland by
the estuary), the eastern shore of the Chesapeake was
reached at a distance of 69 miles 298 perches (rods)
from the point of beginning on Fenwick Island. The
surveyors’ work was approved by the commissioners,
but dissension arose among the latter regarding the
distance to be divided by two for the purpose of locat¬

ing the southwest corner of Delaware. The Maryland
commissioners insisted upon the distance to Slaughter
Creek but those from Pennsylvania pressed for the full
measure to the Bay since Slaughter Creek was only
two feet deep at low water. The lesser distance would
have given Maryland a greater area. Another stale¬
mate having developed, the commissioners adjourned
to await further interpretation on this question and
also those of the incomplete specification of the center
of the town of New Castle and of slope chaining versus
horizontal chaining.

In 1751 Charles, fifth Lord Baltimore, died in Eng¬
land. His eldest son Frederick, sixth and last Lord
Baltimore, then a minor, inherited the title but his
father devised his landed interests in Maryland to his
daughter. This resulted in a court proceeding in
which it was concluded that the land could not be
separated from the title. An odd circumstance of
Frederick’s tenure was that on account of the marriage
articles of his father he was not bound by any agree¬
ments between the previous Penns and Calverts or the
legal decisions earlier rendered in England. He re¬
pudiated all of them and insisted upon a new deed,
which was concluded and signed in July, 1760. How¬
ever, it is to be observed that the boundary outlined
in this instrument closely followed that of the agree¬
ment of 1732. The Lord High Chancellor finally ruled
that the chaining should be horizontal, that the center
of the town of New Castle should be the center of the
belfry of the courthouse, and that the width of the
Eastern Shore should be measured from the shore of
the Atlantic to the shore of the Chesapeake. The posi¬
tion of Cape Henlopen, earlier contested, was defi¬
nitely specified.

In 1760 commissioners were again appointed to see
the survey through. As the matter now stood they were
to locate the mid-point of the transpeninsular line
and from this point run a line tangent to the circle of
twelve miles radius about the belfry of New Castle
courthouse. This circle had been laid out superficially
by two surveyors in 1701 but in the location of the
tangent point the circle in general was not of much
importance. It was required to obtain a perpendicular
intersection with the tangent line at the extremity of a
twelve-mile radial line. Their procedure was to run a
trial line along the meridian of the middle point until
it was near the twelve-mile circle and then from the
belfry of the courthouse at New Castle to run a radial
line to its intersection point with the meridian line.
When the field work was complete, it was found that
the two shorter legs of the triangle were 79 miles 52
chains (79.65 miles) and 7 miles 39.97 chains (7.50
miles) and that the intersection angle was 113°36'.
From these data a trigonometric calculation showed
that the tangent line would make an angle of
3°32'05" westerly from the meridian line and that the
radius from New Castle to the tangent point would
make an angle of 19°03'55" northerly from the south-

8

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

westerly radial line previously run. The commis¬
sioners instructed the surveyors to run the twelve-mile
radial line on the course which had been calculated
and to stake out the line at various points. At the
conclusion of this assignment the field party discon¬
tinued work for the winter on December 2, 1761. In
May of the following year they attempted to run the
tangent line using the calculations referred to above.
Over three months later an intersection was made at a
distance of 81 miles 74 chains 65 links (81.933 miles)
from the middle point and at a point 33 chains 76
links (0.422 mile) east of the extremity of the twelve-
mile radial line. The angle of intersection was found to
be 26 minutes larger than the required 90 degrees.

A second attempt now was made to run the
tangent line. The surveyors were instructed to go to
the end of the twelve-mile radial line and turn off an
angle of 89°55'43" with the radius and in this direc¬
tion to extend a line northward 157 feet 8 inches and
to place a post at this point which was believed would
be the tangent point. Later in the year they returned
to the mid-point of the transpeninsular line and ran
another trial tangent. This line, completed August 19,
1763, passed 5 chains 25 links to the west of the
tangent point positioned as above described. A third
calculation indicated that the true tangent line
would run 2'45” east of the second trial line. How¬
ever, the running of this line was never attempted.
The technological problems were great and involved
the application of much complex geodesy and astron¬
omy, and the progress had been very slow. The Pro¬
prietors had earlier become convinced that the local
surveyors needed assistance and had petitioned the
Astronomer Royal to recommend scientists of ability
to execute the work.

Charles Mason and Jeremiah Dixon were the nomi¬
nees. Their competence had been adequately established.
The former had a long record of distinguished service
at the Royal Observatory, Greenwich, and the latter
had established his reputation as an astronomer on
eclipse and transit expeditions to determine the dis¬
tance to the sun, i.e., solar parallax. A contract was
prepared which was signed by Mason and Dixon and
the Proprietors on August 4, 1763. They arrived in
this country on the following November 15 and by
highly scientific procedures over a period of fifty-eight
months established the common boundaries of Penn¬
sylvania, Delaware, Maryland, and Virginia. The ex¬
cellence of their work has been attested to in more
recent times by checks by such a prestigious organiza¬
tion as the U.S. Coast and Geodetic Survey.

One cannot read the account of the controversy be¬
tween the Penns and the Calverts without amazement
that such a conflict of interest could arise and remain
unresolved for eighty-two years. Its causes were deep-
rooted. One basic reason, earlier mentioned, was the
careless practice of English royalty of assigning terri¬
torial rights that previously had been granted to oth¬

ers. The situation was complicated by the lack of good
maps but this could have been obviated by a little
systematic cartographic work by the English govern¬
ment. Kings lacked competence in scientific matters
and in the writing of their colonial charters made
impossible geometrical specifications. As there were
able scientists in England whose advice would have
averted the resulting confusion, this defect in their
official acts is difficult to excuse. An example is the
specification of a “right line” on an ellipsoid of revo¬
lution. Adjudication was hampered by lack of rapid
transportation. Frequently there was a tendency to
argue matters to which a definite physical answer was
easily available, as was the case with the location of
the fortieth parallel of north latitude along the Dela¬
ware River, which was easily determinable by a com¬
petent surveyor. Again, there was the problem of im¬
possible specifications, an example being the failure of
a circle of twelve miles radius centered in the belfry of
Ne\^ Castle courthouse to reach the fortieth parallel of
north latitude. There were also the untenable posi¬
tions assumed by the respective disputants, examples
being the arguments regarding the radius of the “cir¬
cle at twelve miles distance” and also the disagree¬
ment over the distance from the Atlantic to the Ches¬
apeake. Perhaps the most untenable of all these posi¬
tions was the proposal by commissioners that linear
distances be measured up hills and down valleys,
which would have precluded any type of mathemati¬
cal check on the work. A further source of trouble was
that English courts did not appear consistent in their
decisions and were given to political bias. For ex¬
ample, the cryptic Latin phrase “hactenus inculta”
was interpreted as favoring Maryland in the matter of
Virginia settlements but decided against Maryland in
the matter of the Dutch and Swedes, who actually
were not in that area at the date of the granting of its
charter. To argue that King Charles I introduced this
Latin phrase for the protection of the Dutch and
Swedes requires the greatest elasticity of the imagina¬
tion. The fact is that the English had been continu¬
ally concerned lest their middle Atlantic seaboard
would be permanently severed by these settlements.
Then there seems to have been nothing final about
the decrees of the English courts. At one time procras¬
tination was plainly a cause of the third Lord Balti¬
more’s difficulty, as he had his full forty degrees within
his grasp but he failed to have a survey conducted.

The land areas lost by Maryland and Virginia (now
West Virginia) to Pennsylvania were about 4,300
square miles and 1,100 square miles respectively. The
southern boundary of Pennsylvania was actually placed
19.27 statute miles below the fortieth parallel of north
latitude. As Delaware later became an autonomous
jurisdiction, it is not here considered.

It is difficult to contravene the position of Maryland
as having the earlier grant, but the position of the
Penns seems to have been stronger in circles of English
diplomacy.

III. MASON AND DIXON’S SURVEY

Mason and Dixon arrived in Philadelphia from Eng¬
land on November 15, 1763. On the following day
they attended a meeting of the Commissioners from
Pennsylvania who had been appointed by the Penns
to represent that colony a^nd Delaware in the settle¬
ment of the boundary. They also dispatched a com¬
munication to His Excellency, Horatio Sharpe, Gov¬
ernor of Maryland, announcing their arrival. The as¬
tronomical and geodetic instruments were then landed
and tested, and found to be undamaged. On November

30 the Commissioners appointed by Frederick, Lord
Baltimore, to represent Maryland, arrived in Phila¬
delphia.

December , 1763 , A joint meeting of the Commis¬
sioners was held which lasted several days. The east-
west boundary between Maryland and Pennsylvania
was to follow a circle of latitude 15 miles south of the
southernmost point of the City of Philadelphia. City
officials agreed on the north wall of a house on the
south side of Cedar Street, now called South Street, as
being the southernmost point in the city and on the
circle of latitude from which to measure the 15 miles
southward. A temporary astronomical observatory was
set up near this point and the two geodesists pro¬
ceeded to make observations for latitude. The instru¬
ment they used was a type of astronomical transit
which they called a “sector.” Actually, the observatory
was located 37.15 yards north of the point agreed
upon as the southernmost point of the City of Phila¬
delphia. This was taken as equal to 1.1 seconds of
latitude. Making allowance for this small difference,
the latitude of the southernmost point in Philadel¬
phia was determined to be 39°56'29.1" north. Modern
observations find this to be in error by only 2.5 seconds.

January , 1764 . The above-described determination
was not concluded until the sixth, at which time the
indicated latitude was submitted to the Commission¬
ers from both provinces.

Mason and Dixon were required to move 15 miles
south of this point to begin their border survey be¬
tween Maryland and Pennsylvania. But actually this
position would have been on the opposite side of the
Delaware River, in New Jersey. To obviate this com¬
plication, it was decided to move westward along the
circle of latitude of the southernmost point of Phila¬
delphia to the Forks of the Brandywine River, about

31 miles distant. To guide them in this approximate
determination of latitude, a navigator’s quadrant was

utilized and a point arrived at very near the house of
a Mr. John Harland. The observatory on Cedar Street
in Philadelphia was disassembled and transported to
this new position and later set up in the Harland
yard. Extreme care was exercised in the transporta¬
tion of the fragile instruments, which were placed on
a featherbed in a wagon. It appears to have required a
two-day trip by horse team to cover the 31 miles. The
observatory not yet being ready, the astronomical
transit or sector was promptly put in place in a tent,
and a set of observations for latitude was begun on
the fourteenth of the month. Later the instrument was
moved to the observatory. The position of the sector
in the tent was 9.5 yards north of its later position in
the observatory; this necessitated a small correction of
negative 0.3 second of latitude for observations in the
tent. On the twenty-sixth a series of latitude observa¬
tions was begun to determine the position of the
observatory.

February , 1764 . The observations were continued
until the twenty-eighth. Four days prior to this date,
wooden levels were brought for measuring the 15
statute miles horizontally. The mean of the latitude
observations showed the observatory, i.e., the sector, to
be 356.8 yards south of the parallel of latitude
through the southernmost point in the City of Phila¬
delphia. At this time Mason stated that, if the value of
a degree, 69.5 miles, were later found to be slightly in
error, the 356.8 yards would be adjusted accordingly.
The reduction of the astronomical observations
showed the latitude of the observatory in Mr. John
Harland’s yard in the Forks of the Brandywine River
to be 39°56'18.9", this being 10.2 seconds less than that
of the southernmost point in the City of Philadelphia.

March , 1764 . Progress during the first half of the
month was much impeded by cloudy and falling
weather which made astronomical observations im¬
possible. On the fifth an observation for azimuth was
made by observing Polaris at upper culmination and
this direction was proved on the sixteenth. On the
seventeenth an eclipse of the moon was observed to
end at 8h21m59s apparent time. Mason remarked,
“The edge of the sun’s shadow was the best defined I
ever saw, the air was so clear it was remarkably dis¬
tinct from the penumbral shade.”

About the middle of the month the survey party
was enlarged by the employment of axmen to cut out
a vista southward along a meridian from the observa-

0

10

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

Fig. 2. Map illustrating the surveys of the Pennsylvania-Maryland-Delaware boundaries, 1730-1764.

tory on the Hg,rland plantation until a point 15 miles
south of the parallel of the southernmost point in
Philadelphia had been reached.

April, 1764 . Work was begun to measure accurately
the required distance southward. This measurement
was accomplished by the use of levels, i.e., wooden
rods, 16.5 feet in length, evidently with a spirit level
attached, whereby truly horizontal distances were as¬
sured. The path of chaining was, of course, the vista
which the axmen had cut out in the direction of true
south as earlier established by an astronomical obser¬
vation on Polaris.

On the fifth a confirming observation was made,
proving the first determination of the meridian to be
very exact. A week later a point 15 miles south had
been reached. In this chaining, allowance was made
for the fact that the observatory in Brandywine was
10.5 seconds too far south. The following day the sur¬
veyors returned to Brandywine with the laborers, dis¬
assembled the observatory, and moved it and the as¬

tronomical instruments and other equipment in four
wagons to the end of the 15-mile line which was in a
field of a Mr. Alexander Bryan. The next step was to
assemble the observatory at that point.

At this time Mason and Dixon left for Philadelphia
to inform the Commissioners of their arrival at the
southern extremity of the 15-mile line. His Excellency,
Horatio Sharpe, Governor of Maryland, also was in¬
formed. The field assistants had been furloughed and,
the remaining five days of the month being inclement,
nothing further was accomplished.

May, 1764 . During the first twelve days the astron¬
omers occupied themselves in making a latitude de¬
termination at the south end of the 15-mile line. Be¬
fore reducing the observations, they decided to check
the length of the line, and on the fourteenth of the
month a remeasure running northward was started
with the aid of five men. A small correction had to be
made for slope distances measured on hills where the
levels were not used. Allowing for this, the final posi-

MASON AND DIXON'S SURVEY

12

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

Fig. 4. Map illustrating the surveys of Mason and Dixon.

tion of the southern extremity of the 15-mile line was
definitely settled upon. On the nineteenth the two
geodesists attended a meeting of the Commissioners
from both provinces at New Castle and, after their
return to the observatory in Mr. Bryan's field, made
additional stellar observations for latitude on two
nights. On the twenty-first and twenty-second they
were again in conference with the Commissioners at
New Castle. Following this, Mason and Dixon made
additional latitude. (zenith distance) observations until
the end of the month. There were several nights of
cloudy weather during this period when no astronomi¬
cal work could be accomplished.

June, 1764 . Zenith distance readings were con¬
tinued until the ninth of the month, at which time
the scientists spent about four days in reducing all
observations. The latitude of the southern extremity
of the 15-mile line was found to be 39°43'17.4" north
(page 103 of the Journal). This would be the geo¬
graphic latitude of the West and East Lines of the
Pennsylvania-Maryland border. The Commissioners
had determined that the geodesists should now proceed
to the “Middle Point" to run the Tangent Line. Spe¬
cifically, the Middle Point was a position on the
present-day Delmarva Peninsula supposedly midway
on a great circle (starting at N90°W) between Cape
Henlopen and the Chesapeake Bay. It subsequently
came to mark the southwest corner of Delaware. The
Tangent Line is a line running slightly northwesterly

(N3°43'30"W) from the Middle Point to a point of
tangency with a circle of 12 miles radius around the
belfry of New Castle courthouse. This line was to be
the boundary between Maryland and Delaware (then
included in the dominions of the Penns) along their
respective eastern and western borders. Concurrently
with this change in assignment, Mason and Dixon
proceeded on the thirteenth of the month to pack up
their scientific instruments and other equipment and
make their way by wagons to New Castle, which was
reached the following day. Axmen earlier furloughed
were reemployed to assist in the new project. On the
eighteenth the survey party left New Castle and ar¬
rived at Dover the following night. They encamped
four nights later on the banks of the Nanticoke River,
where tents were temporarily pitched. On the next
day additional axmen were employed. The entire
party, including a steward, tentkeepers, cooks, chain
carriers, axmen, etc., now numbered thirty-nine per¬
sons—exceeding in size a present-day triangulation
party of the Coast and Geodetic Survey. Equipment
for travel included two wagons and eight horses. On
the twenty-fifth the party with its equipment crossed
the river in canoes, proceeded to the Middle Point,
and began to run from thence a great circle arc in the
northerly direction determined by geodetic calcula¬
tions to give tangency to the circle of 12 miles radius.
On the last day of the month they had again reached
the Nanticoke. The river at this location is too wide to
chain by usual procedures but the two scientists ac-

MASON AND DIXON'S SURVEY

13

curately determined its breadth by triangulation. A
base line 8 chains in length was measured along the
river shore. By determining two of the angles with a
Hadley quadrant, a distance of 9 chains 4 links (596.6
feet) was found for the width of the stream at this
point. Mileposts were accurately set at each mile
point as the boundary survey progressed and at this
location a distance from the Middle Point to the south
bank of the Nanticoke was given as 6 miles 70 chains
25 links, i.e., 6.878 miles.

July, 1764 . The line was pushed northward and at
the end of the month the 48-mile point had been
reached. The Choptank River was crossed near mile¬
post forty-two. The stone marker which later replaced
the temporary wooden marker now lies submerged
behind a dam.

August, 1764 . The line was continued northward
until the twenty-fifth, at which time a distance of
slightly over 81 miles from the Middle Point had been
reached, at a point judged to be a little beyond the
point of tangency with the 12-mile circle around New
Castle courthouse. The sixty-ninth milepost had been
set on the south side of the Bohemia River near the
low water mark. On the eighteenth of the month, let¬
ters were sent to Horatio Sharpe, Esquire, Governor of
Maryland, and to Mr. James Hamilton, Commissioner
from Pennsylvania, stating that the line would reach
the Tangent Point in eight or ten days. On the twenty-
fifth of the month the Journal reports: “Set the 81st
mile post and produced the Line till we judged we
were past the Point settled before to be the Tangent
Point in the circle round Newcastle of 12 Miles
Radius.” The next day a wagon was dispatched to
Philadelphia to purchase additional tents. On the
twenty-seventh of the month the radial line from the
belfry of New Castle courthouse, earlier determined
upon by colonial surveyors as running to the Tangent
Point, was produced to the line which had just been
run from the Middle Point. The distance between the
actual intersection point and the point previously
considered to be the Tangent Point was 22.51 chains
(1485.66 feet). The length of the Tangent Line as just
run to the point of intersection was 81 miles 78 chains
31 links (page 77). Mason comments: “The distance
will be 81.78.25 when at right angles: and the Per¬
pendicular to the 12 mile Post, 22.50 chains.” He also
comments: “The angle made by our line and the
radius produced from New Castle is 89° 50"—Mea¬
sured by a Hadley’s Quadrant.”

September, 1764 . Accurately establishing the Tan¬
gent Line now involved the preparation of tables of
offsets, whereby the previous work was successively
improved. They now proceeded to place temporary
markers at the 5-mile points, working southward to¬
ward the Middle Point. On the tenth of the month

Mason records that the party was at a Mr. Twiford's
on the bank of the Nanticoke River where they
awaited for two days the arrival of the wagons with
supplies.

Near the middle of the month Mason remarked that
he went to see the Pocomoke Swamp and gave this
description:

It’s about 30 Miles in Length and 14 in breadth: (The West
Line [Trans-peninsula] from the Sea to the Middle Point
passes through it) : There is the greatest quantity of Timber
I ever saw: Above the Tallest Oak, Beech, Poplar, Hickory,
Holly and Fir; Towers the lofty Cedar: (without a
Branch), till its ever green conical top; seems to reach the
clouds: The pleasing sight of which * renewed my wishes to
see Mount Lebanon (page 81).

The great Pocomoke Swamp lies partly on both sides
of the boundary line between Maryland and Delaware
which runs west from Fenwick Island where Cape
Henlopen lies and is roughly in the vicinity of Selby-
ville, Frankford, and Gumboro in Delaware and Whal-
eysviile in Maryland. During the next twelve days,
work was continued southward in measuring the off¬
sets to improve the tangent until the Middle Point
was reached on the twenty-fifth, when the scientists
returned to Mr. Twiford’s. The rest of the month was
spent in still further improving the Tangent Line.

October, 1764 . During this month additional effort
was expended on further approximations to perfect
the Tangent Line. This consisted of measuring offsets
to the final position from points of predetermined
error.

November, 1764 . The work of improving the ap¬
proximations was continued until on the twelfth
Mason declared that the tangency was so nearly in
agreement with mathematical requirements that it
was the true Tangent Line in so far as any practical
necessity was concerned. The required angle of 90° at
the intersection was substantially met and the linear
discrepancy seems to have been only about 26 inches.
On the same day communications were dispatched to
Governor Sharpe of Maryland and Mr. Joseph Hamil¬
ton, Commissioner from Pennsylvania, informing them
of the completion of the work. The following week
Mason and Dixon spent in waiting for the Com¬
missioners from Pennsylvania and Maryland who as¬
sembled on the twenty-first at Christiana Bridge in
New Castle County. At this time they were in agree¬
ment that the project of establishing the Tangent
Line had been satisfactorily concluded. On the twenty-
sixth of the month all survey helpers were furloughed
for the winter season and Mason and Dixon returned
to the home of Mr. John Harland at the Forks of the
Brandywine.

December, 1764 . This month was without activity
except that a letter was written to the Proprietors to in¬
form them that the Tangent Line had been established.

14

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

January, 1765 . During this month no technical
work was accomplished. A visit was made to Lancaster
and Pechway, and they returned to Brandywine on
the nineteenth.

February , 1765 . Mason left Brandywine on the elev¬
enth and proceeded to New York. He records that his
horse was nearly lost in crossing the Delaware on ice.
The route took him through Princeton. He com¬
mented that the college was the most elegantly con¬
structed he had seen in America. The next four days
were spent in New York, but then began his return by
New Jersey and on the twenty-seventh he crossed the
Delaware to New Castle and proceeded to Newark,
Delaware.

March, 1765 . Mason and Dixon now began prepara¬
tions to run the “West Line,” i.e., the line running
westerly from the northeast corner of Maryland. Con¬
siderable time was spent in performing astronomical
observations for azimuth to give the direction on
which to start the first great circle arc of 10 minutes.
(Journal, page 107 et seq.) As a consequence of incle¬
ment weather and other reasons not recorded, no fur¬
ther work was attempted until the twentieth. A deep
snow followed the next day which the Journal entry
gives as nearly three feet in depth on the level. No
further technical work was accomplished this month.

April , 1765 . On the fifth of the month Mason and
Dixon proceeded to run the West Line, using for the
first 10-minute arc of great circle a direction deter¬
mined by calculations of spherical trigonometry and
observations referred to above. Their measurements
were from a “Post marked West” in Mr. Bryan’s field,
which in latitude was IS miles south of the southern¬
most point in Philadelphia, and later turned out to be
2 miles 79 chains 27 links east of the northeast comer
of Maryland. The survey proceeded westward, cross¬
ing Little Christiana Creek, Great Christiana Creek,
and the Elk River. On the thirteenth a point had
been reached near the end of the 10-minute arc of
great circle, i.e., at 12 miles 25 chains from the point
of beginning. At this time the scientists returned to
the end of the line and came back with the astronomi¬
cal transit or sector. The following day they set it up
at the point reached on the thirteenth, to obtain a
check on its latitude. The mean of the observations
showed that the position of the sector was 1.29 seconds
of arc north of the parallel through the Post marked
West. A table of offsets was now prepared which took
into consideration the distance from the great circle
southward to the parallel and also the amount (129
feet) by which their line had erred from the desired
great circle. The calculated offsets were measured off
from the great circle by returning eastward and a tem¬
porary monument was placed at every mile point. The
positions marked the true boundary between Maryland

and Pennsylvania. On the twenty-ninth of the month
they proceeded to repeat the procedure, i.e., to run a
second arc of great circle of 10-minute length. The fol¬
lowing day they crossed the main branch of the North
East River at a distance of 14 miles 2 chains from the
Post marked West. At this time communications were
dispatched to the Commissioners from Maryland and
Pennsylvania to inform them that the survey would
reach the Susquehanna River in twelve days.

May, 1765 . The line was continued without inter¬
ruption for nearly two weeks, during which time the
route crossed the Octoraro River three times in quick
succession. The river was very sinuous but each cross¬
ing was nearly perpendicular to its banks. The three
crossings respectively began 20 miles 61 chains, 20
miles 71 chains, and 21 miles 25 chains, and the width
of the river was recorded by Mason as about 50 yards.
Conowingo Creek was crossed at 23 miles 67 chains,
and at a distance of 25 miles 75 chains 57 links the end
of the 10-minute arc of great circle was approximately
reached. The sector was set up and latitude observations
were made for two weeks. When the star positions had
been reduced, a deviation from the standard parallel of
3.82 seconds of arc or 382 feet to the north was found.
A table of offsets from the chord to the parallel was com¬
puted, from which the true boundary between Maryland
and Pennsylvania could be staked out when the party
began to move eastward. About this time the width of
the Susquehanna River was determined by triangula¬
tion. Instead of employing a right triangle as is com¬
mon practice among civil engineers, they apparently
were forced into the device of using an oblique tri¬
angle, for which no reason is in evidence except that
of necessary visibility between vertices. The calculated
distance across the Susquehanna was 67 chains 68
links (0.846 mile). As in the case of the triangulation
on the Nanticoke, the goniometry was carried out
with a Hadley quadrant of 18 indies radius. A stake
was placed on the west side of the Susquehanna River
at a distance of 26 miles 72 chains 71 links from the
Post marked West. The position was about 16 miles
north of the headwaters of the Chesapeake Bay and
about 57 miles southwesterly from Philadelphia. On
the twenty-eighth the instruments were packed up and
the survey party worked its way eastward while mea¬
suring the offsets at the mile points from the survey
line to the true parallel of the Post marked West, thus
marking the true boundary between Pennsylvania
and Maryland.

June , 1765 . On the first of June, Mason and Dixon
returned to the Tangent Point not far from the Post
marked West in Mr. Bryan’s field. Here they made
astronomical observations on Polaris and Alioth to es¬
tablish the meridian which was necessary in order to
run such a line due north from the Tangent Point, as
required by the Commissioners. The North Line ac-

MASON AND DIXON'S SURVEY

15

tually extended from the Tangent Point to the north¬
east corner of. Maryland, intersecting the circle of 12
miles radius as a secant. The boundary between Mary¬
land and Delaware in this part of the survey actually
follows the circle, and the North Line at present is
considered to extend from the point where it leaves
the circle, to the northeast corner of Maryland. This
line is short and the mission was quickly accom¬
plished. On the third of the month Mason and Dixon
sent communications to Annapolis and Philadelphia
to inform the Commissioners that the North Line
soon would be complete. Mathematical studies now
were made to ascertain the length of the line as a
secant, and this was found to be 1 mile 36 chains 10
links (1.451 miles) (page 131 and also page 133). Off¬
sets on the segmental area of the circle of 12 miles
radius were computed. These offsets were measured
from the secant and were temporarily marked by
wooden stakes. This locus of points was the Arc Line.
The distance from the Tangent Point to the parallel
through the Post marked West was measured as 5
miles 1 chain 50 links (5.019 miles) (page 134). The
point of intersection of these two lines was the north¬
east corner of Maryland. The meridian from the
Tangent Point crossed the required parallel 2 miles 79
chains 27 links (2.991 miles) west of the Post marked
West. That is to say, the Post marked West was this
distance east of the northeast corner of Maryland. In
order that the permanent granite mileposts might
stand at even miles from this latter point, all such
markers were placed 73 links east of the temporary
markers along the West Line. A post bearing a W on
the west side and N on the north side was placed at
the intersection point at the northeast corner of Mary¬
land. The field work was completed on the seventh of
the month. A delay of nine days now resulted, during
which a meeting of the Commissioners was awaited,
but on the seventeenth they met at Christiana Bridge
in New Castle County. Seven permanent boundary
stones were set as follows: one at the Tangent Point,
four on the Arc Line above described, one on the
North Line, and one at the intersection of the North
Line with the main parallel, i.e., at the northeast cor¬
ner of Maryland. The Commissioners now instructed
the geodesists to extend the parallel westerly from the
Susquehanna as far as the country was inhabited.
Germane communications were dispatched to the
Proprietors of Maryland and Pennsylvania. The party
returned to the Susquehanna and after changing di¬
rection proceeded to extend the West Line from the
point where work had been discontinued in order to
establish the Arc Line and the North Line. At 28
miles 69 chains the route crossed the road leading
from York to Rock Run. A schoolhouse was located
one chain southward.

July, 1765 . The line was continued during the first
three days, at which time the surveyors had reached a

point 37 miles 17 chains 98 links west of the Post
marked West and believed they were again on the
true parallel. A change in direction was made without
latitude observations and the line was continued,
crossing Deer Creek at 46 miles 40 chains. At a dis¬
tance of 48 miles 64 chains 5 links they believed that
the parallel again had been reached and made a series
of observations which required about ten days. Re¬
duction of the zenith distances showed them to be 0.56
second of arc or 56 feet south of the true parallel. A
table of offsets was computed for the two previous 10-
minute arcs, by which the distances to the boundary
points could be measured. During the remaining week
a new direction was laid off so as to intersect the
parallel again at 10 minutes of great circle farther
west. At 49 miles 7 chains the party crossed the “lower
Road leading from York to Joppa and Baltimore,”
and at 52 miles 18 chains crossed the main branch of
the Gunpowder River and at 60 miles 33 chains
crossed the last branch, at which position on the thir¬
tieth they believed they were again nearly on the par¬
allel. No celestial observations were made but the di¬
rection was changed so as to intersect the parallel at
10 minutes westward.

August , 1765 . The line was continued and crossed
several creeks including the Codorus, Coniwago, and
Piney, a branch of the Monocacy. At 71 miles 43
chains 19 links the surveyors believed they again had
reached the parallel. On the seventh the astronomical
transit was set up and a series of stars was observed for
latitude. Mason recorded that a great hailstorm oc¬
curred at that time, one hailstone measuring 1.6 x 1.2 x
0.5 inches. Observations of zenith distance were con¬
tinued through the eighteenth, following which about
two days were spent in calculating the results, which
showed the position of the sector to be 4.58 seconds
north of the true parallel, the error amounting to 458
feet. A table of offsets from the great circle to the
parallel was prepared for the previous two 10-minute
arcs of great circle in order to stake out the boundary
at a later date. The direction was now changed so as
to intersect the parallel again at the end of a 10-
minute arc of great circle. En route the survey crossed
Piney Run, Monocacy Road, Willolloway Creek, Rock
Creek, Mash Creek, and Middle Creek and at 83 miles
13 chains 96 links Mason and Dixon again believed
they were on the true parallel. No latitude check was
made. The direction was changed, so as to be near the
parallel at the end of another 10-minute arc of great
circle. At 86 miles 44 chains the foot of South Moun¬
tain was reached. On the thirtieth day of the month
the party was at 88 miles 00 chains west of the Post
marked West.

September, 1765 . The line was continued and at 93
miles 63 chains and 94 miles 62 chains two springs
were crossed running into Antietam Creek. The last

16

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

spring was at the foot of South Mountain on the west
side. At 94 miles 63 chains 10 links the astronomical
transit was again set up and a series of latitude ob¬
servations was carried out over a period of nine
nights. Reduction of the observations showed the
point of observation to be 0.56 second of arc or 56 feet
south of the true parallel. A table of offsets was cal¬
culated to give the distances to be measured off at the
various mile points west of the position where obser¬
vations were made on the seventh of August at 71
miles 43 chains. The boundary points would be estab¬
lished later.

The running of the line was resumed on the twen¬
tieth in the direction to intersect the parallel at 10
minutes of great circle. At 95 miles 38 chains the line
crossed a spring running into Antietam Creek. On
Sunday, the twenty-second of September, Mason com¬
ments :

Went to see a cave (near the Mountain about 6 miles South
of Mr. Shockey's). The entrance is an arch about 6 yards
in length and four feet in height, when immediately there
opens a room 45 yards in length, 40 in breadth and 7 or 8
in height. (Not one pillar to support nature's arch) : There
divine service is often (according to the Church of Eng¬
land) celebrated in the Winter Season. On the sidewalks are
drawn by the Pencil of Time with the tears of the Rocks:
The imitation of Organ, Pillar, Columns and Monuments of
a Temple; which with the glimmering faint light; makes
the whole an awful, solemn appearance: Striking its Vis¬
itants with a strong and melancholy reflection: that such is
the abodes of the Dead: Thy inevitable doom, O Stranger;
Soon to be numbered as one of them. From this room there
is a narrow passage of about 100 yards at the end of which
runs a fine river of water: On the sides of this passage are
other rooms but not so large as the first (page 166).

Unfortunately, the cave, which was about 8 miles
east of Hagerstown, near Cavetown, Maryland, has
been destroyed by rock-quarrying in recent years. At
99 miles 35 chains the line crossed Antietam Creek and
at 103 miles 69 chains it intersected a road leading to
Swaddingem's Ferry on the Potomac. On the twenty-
sixth, at 105 miles 78 chains 67 links, the direction was
changed so as to be again on the parallel at the end of
another 10-minute arc. No latitude check was made.
The twenty-ninth being Sunday, Mason went south to
the Potomac and forded to the Virginia side, where a
log fort and a tavern were located. On the last day of
the month the line crossed Conecocheague Creek at a
distance of 109 miles 14 chains from the Post marked
West.

October, 1765 . The line was continued until on the
seventh a distance of 117 miles 12 chains 97 links had
been attained and at this point the sector was set up
for a latitude check. For the next seventeen days the
two astronomers were engaged in making zenith dis¬
tance observations. The reduction of the readings
showed the sector to be 8.47 seconds or 847 feet south
of the parallel. From this information a table of offsets

was calculated for the last 22.373 miles. On Sunday,
the twenty-seventh, Mason recorded: “From here we
could see the Allegany Mountain for many miles, and
judge it by its appearance to be about 50 Miles [in]
distance, in the direction of our Line” (page 178).
The two geodesists now set out, on the twenty-eighth,
on their return eastward to the Susquehanna to mea¬
sure off the offsets from the great circle arcs to the true
parallel, thus marking the true boundary between
Maryland and Pennsylvania. By the end of the month
they had reached the seventy-fourth milepost.

November, 176 5 . The party continued moving east¬
erly and measuring the distances from the great circle
to the parallel and placing temporary posts at the mile
points until the sixth of the month, at which time the
twenty-seventh milepost near the west bank of the
Susquehanna was reached. The following day the
river was crossed at Peach Bottom Ferry. All help was
furloughed for the winter season and on the eleventh
Mason and Dixon left the Ferry for York to attend a
meeting of the Commissioners which lasted four days.
On the twenty-first they left York and proceeded to
the Middle Point to set fifty permanent boundary
markers in the Tangent Line, i.e., one at each mile
point running northerly.

December, 1765 . On the fifth the two scientists ar¬
rived at Mr. Twiford's on the Nanticoke and appar¬
ently remained there to await the arrival of the
boundary stones from England. On the seventeenth,
twenty such stones arrived on the Nanticoke and
about the same time thirty arrived on the Choptank.
At every 5 miles a stone was placed, bearing the coat of
arms of the Penns on one side and that of the Balti-
mores on the reverse side. At intermediate mile points
the markers were carved with a P on one side and an
M on the reverse side.

January, 1766 . Mason and Dixon left off for the
winter season. There was no activity during this
month except a trip to Philadelphia. On the sixth
letters were written to the Proprietors of Pennsylvania
and Maryland. Throughout the remainder of the
month it appears they were at Mr. John Harland's
home at the Forks of the Brandywine.

February, 1766 . On the twenty-first of the month
Mason “Left Brandywine and proceeded for curiosity
to the Southward to see the Country” (page 180).
From the text it does not appear that Dixon accom¬
panied him. His route took him across the Susque¬
hanna at Nelson's Ferry about 7 miles north of the
Maryland border and from there to York, Pennsyl¬
vania; Frederick, Maryland; Alexandria, Dumfries,
and Stafford Court House in Virginia. The latter
town, about 40 miles south of Georgetown, Maryland,
now a part of the City of Washington, D.C., was
reached on the last day of the month.

MASON AND DIXON’S SURVEY

17

March, 1766 . Mason lodged near Port Royal on the
Rappahannock River on the night of the first, and the
next day crossed the river and remained for an addi¬
tional day before proceeding on his route, which took
him over the Pamunkey River and on to Williams¬
burg, described by him as the “Metropolis of Vir¬
ginia,” which he reached on the third. The following
day he departed on his return by way of Port Royal
and Hoe’s Ferry on the Potomac, near the present
Morgantown toll bridge, and lodged for the night at
Port Tobacco, Maryland. On the eighth he was near
Upper Marlboro and on the eleventh reached An¬
napolis, which he described as “the Metropolis of
Maryland.” Two days later he “compared with His
Excellency, Horatio Sharpe, Esq., a copy of our Jour¬
nal.” On the fifteenth he left Annapolis and pro¬
ceeded to North Mountain to continue the boundary
survey. Two days later he had reached Frederick near
South Mountain. On the eighteenth Dixon left Phila¬
delphia to attend a meeting of the Commissioners on
the twentieth at Chestertown on the Eastern Shore.
The following day instructions were received to pro¬
ceed with the line to the Allegheny Mountains. During
the next three days the only activity was that the party
furloughed in the early winter made rendezvous near
Captain Shelby’s at the foot of North Mountain.

April, 1766 . The running of the line was now re¬
sumed. A direction to intersect the parallel in 10
minutes had been established the previous October.
The head of Little Licking Creek running into
Conecocheague was passed at 118 miles 63 chains. At
119 miles 18 chains the summit of North Mountain
was reached. Fort Frederick was nearly 8 miles south
and Fort Loudon near Parnel’s Nob in Pennsylvania
was about 11 miles north. With the exception of one
day, operations were discontinued for twelve days, this
being a period of inclement weather which also de¬
layed the arrival of equipment. Operations were re¬
sumed on the seventeenth and at 122 miles 67 chains
Great Licking Creek was crossed at the foot of North
Mountain on the West Side and on the twenty-third
at 129 miles 12 chains 04 links the direction was
changed so as to intersect the parallel 10 minutes west.
The next day, the twenty-fourth, the party appears to
have reached a point on the meridian of the narrowest
point in Maryland, close to Hancock. The Journal
records as follows: “At 129^4 miles by estimation the
Northernmost bend of the River Potowmack Bore
South distant about a mile and a half. At 134 miles 54
chains the foot of Sidelong [Sideling] Hill was
reached.” On the twenty-ninth the end of the 10-
minute arc was attained at a distance of 138 miles 50
chains. The sector, which had been left at Captain
Shelby’s was sent for in order to make a series of lati¬
tude observations.

May, 1766 . On the fourth the sector was set up near

the end of the 10-minute arc of great circle at a dis¬
tance of 140 miles 15 chains 76 links from the Post
marked West. Astronomical observations were made
during the following twelve days. Reduction of the
zenith distances showed the sector to be 0.20 second or
20 feet south of the true parallel. A table of offsets for
the last two 10-minute arcs of great circle was now
computed, but measurements of offsets were made at a
later date. On Sunday, the eighteenth, the instru¬
ments were packed up and the party proceeded on the
next 10-minute arc after having changed direction to
intersect the parallel. At 143 miles 77 chains Fifteen
Mile Creek was crossed. The summit of Great Warrior
Mountain was reached at 151 miles 48 chains on the
twenty-seventh. At this point direction was again
changed so as to meet the parallel at 10 minutes west.
On the last day of the month they crossed Wills Creek
at 161 miles 25 chains from the Post marked West.

June, 1766 . The line was continued until the ninth,
when the end of the 10-minute arc of great circle was
reached at a distance of 165 miles 54 chains 88 links
from the Post marked West, at which position the
sector was set up and latitude observations were made
on clear nights until the fifteenth. The reduction of
these zenith distances showed the position to be 2.41
seconds or 241 feet to the south of the true parallel. A
table of offsets was computed for laying off the true
boundary. Interesting notes in the Journal under the
date of the fourteenth read in part: “From the soli¬
tary tops of these Mountains, the Eye gazes round
with pleasure; filling the mind with adoration to that
pervading spirit that made them.” On the eighteenth
the party proceeded to work backward toward the
Post marked West and to lay off the calculated offsets
from the great circle to the parallel. On Sunday, the
twenty-second, a comment is observed that the route
of General Braddock was crossed “which he cut
through the. Mountains to lead the Army under his
command to the Westward in the year 1755, but fate;
how hard: made through the desert a path, himself to
pass; and never; never to return.” On the twenty-
eighth the marking of the positions for the boundary
markers was complete as far as the milepost 154.

July, 1766 . The marking of the boundary was con¬
tinued by measuring the offsets from the great circle
and on the fifth, milepost 140 was reached. On the
sixth, Mason noted that he measured three leaves on
one stem of a hickory tree, each of which was 17 inches
in length and 12 inches in breadth. The following day
he commented that he was able to observe the circle of
latitude which had been cut out and that as viewed
from the promontory of Sideling Hill it “formed the
arch of a lesser circle very agreeable to the laws of a
sphere.” On the twenty-sixth the boundary points had
been located eastward to milepost 107 and this effort
was continued for the remainder of the month.

18

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

August, 1766 . The work of measuring the offsets to
the true boundary between Pennsylvania and Mary¬
land was continued. On the fifth of the month an
eclipse of the sun was observed which from the nota¬
tion of Mason would appear to have been about 70
per cent total. It began about llh20m and ended at
2h20ml7s. On the ninth the line had been laid out to
milepost 85 and on the sixteenth to milepost 73. On
the twentieth an eclipse of the moon was observed
which was recorded as about 50 per cent total. Mea¬
surements of the offsets were continued until the end
of the month, at which time milepost 44 had been
reached.

September, 1766 . The work of measuring the offsets
from the great circle to the parallel was continued and
on the twelfth communications were sent to An¬
napolis and Philadelphia to acquaint the Commission¬
ers that the marking of the West Line to the extent
of the field work would be finished on the twenty-
seventh of the month. Actually, on the twenty-fifth an
intersection was made between the true parallel and
the meridian through the Tangent Point extended
northward, i.e., the northeast corner of Maryland.
This fulfilled the surveyors’ instructions to that date.
On the same day Mason again commented that from
any eminence where 15 or 20 miles of the marked
parallel could be observed, the geometrical properties
of the sphere were in evidence. He also noted that the
total number of boundary posts set up to that time in
the West Line was 303, or about one to each half mile.
Intermediate positions evidently were interpolated as
the offsets were calculated for only full-mile positions.
A “Visto” about 8 yards wide was cut out along the
border between the two provinces. On the twenty-
seventh a letter was received from the Commissioners
stating that they would meet the two geodesists at
Christiana Bridge in New Castle County on the
twenty-eighth of the next month. On the last day of
the month the field party was furloughed.

October, 1766 . On the first day of the month Mason
and Dixon were in Newark in New Castle County. The
above-mentioned letter conveyed the information that
agreement had been reached in the matter of their

employing the interval of time to the 28th Instant, in exe¬
cuting our instructions from the Royal Society of London;
towards determining the Length of a degree of Latitude (of
which Instructions the Commissioners of both Provinces
had received notice from the Honorable: the Proprietors:
To whom we wrote in June 1765 for leave to use their In¬
struments; and the indulgence to do it in their Provinces).
Accordingly from this information we this day set out with
the Sector* etc. for the Middle Point, or South end of the
Tangent Line; To execute the Instructions from the Royal
Society.

* The telescope part, carried by three men.

The work of determining the dimensions of the
earth on the Delmarva Peninsula was not considered
to be closely related to the separation of the domin¬
ions of the Penns and the Calverts, and for that reason
will be discussed in a separate chapter.

On the twentieth of October the instruments were
packed up at the Middle Point and sent to Newark,
Delaware, where Mason and Dixon arrived on the
twenty-fourth. Instructions were received on the twenty-
ninth that one hundred boundary stones were to be
set on the Tangent Line, and on the West Line one
at each mile point.

November, 1766 . The above assignment apparently
occupied their time during the first half of the month.
On the eighteenth, nineteenth, and twentieth Mason
and Dixon attended a meeting of the Commissioners
at Christiana Bridge. The stones had all been set in
the Tangent Line and for 65 miles on the West Line,
i.e., the boundary between Maryland and Pennsyl¬
vania, but no stone was placed at the sixty-fourth-mile
position from the northeast corner of Maryland. In
the setting of the stones one of the Commissioners of
each province was present. On the twenty-first Mason
and Dixon attended a meeting of the Commissioners,
when instruction was given that the parallel of lati¬
tude of the Pennsylvania-Maryland border should be
extended eastward from thg northeast corner of Mary¬
land to the Delaware River. A complication was also
to be resolved: Indian opposition had made hazardous
the extension of the West Line beyond the point
reached on June 9, 1766. This problem was referred to
Sir William Johnson, His Majesty’s Agent for Indian
Affairs in the Colonies, who attempted to gain the
consent of the Six Nations. On the twenty-fifth Mason
and Dixon proceeded to extend the parallel of lati¬
tude eastward from the northeast corner of Maryland
to Delaware Bay. The length of this line had to be
determined in order that the 5 degrees of longitude
along Pennsylvania’s southern border could be mea¬
sured from Delaware Bay. The usual method of
running great circle arcs of ten minutes and measur¬
ing offsets was employed. On the twenty-fifth the small
deflection was turned off at the Post marked West and
the work proceeded eastward. The bank of the Dela¬
ware was reached on the thirtieth at a distance of 11
miles 20 chains 88 links east of the Post marked West.
The offset at this point, not being at the extremity of a
great circle arc, was actually 7 feet south thereof. No
latitude observations were made.

December, 1766 . The following day a wooden post
was placed at the point referred to above, i.e., on the
bank of the Delaware and in latitude 15 miles south
of the southernmost point of the City of Philadelphia.
Mason and Dixon again turned their attention to
measuring the length of a degree of latitude in the
region chosen for this purpose. On the fifth of the

MASON AND DIXON’S SURVEY

19

month they were again at Brandywine, where they set
up the sector at Mr. John Harland’s and made addi¬
tional observations in the same parallel where similar
work had earlier been done in January, 1764. Obser¬
vations of zenith distance, for the determination of
the length of a degree of latitude, occupied nearly all
of the month.

January , 1767 . Most of the month was taken up
with standardizing the clocks in connection with the
geodetic work of the Royal Society. This would ap¬
pear to have been a very cold winter. On the first day
of the month Mason reported a temperature of twenty-
two degrees below zero F. and commented: “In recti¬
fying the Instrument for the Equal Altitude; the
immediate touch of the brass was like patting one’s
fingers against the points of Pins and Needles; the
Cold was so intense.”

February , 1767 . Standardization work was con¬
tinued. Some studies were made on the time of immer¬
sion and emersion of the satellites of Jupiter. This
work was related only to the Royal Society’s project.

March, 1767 . During the first two and a half weeks
numerous meteorological data were recorded. On the
twenty-second the scientists left Brandywine for New
Town (Chestertown) on the Chester River to attend a
conference with the Commissioners on the twenty-
fourth, But at the end of the next day the latter had
not arrived and Mason and Dixon left for Annapolis
where they were apprised by Governor Horatio Sharpe
that the meeting had been postponed until the twenty-
eighth of the following month. From there they re¬
turned to Brandywine.

April, 1767 . The scientists left Brandywine on the
seventh and were in Philadelphia on the eighth and
ninth. Here they were informed by the Commissioners
for Pennsylvania that no answer had been received
from Sir William Johnson as to whether a further
extension of the West Line would be permitted by the
Indians. On the seventeenth they were again at
Brandywine but left in about a week and about the
twenty-fifth were in Philadelphia, where they were in¬
formed that arrangements with the Indians were still
incomplete. They returned to Brandywine at the end
of the month.

May, 1767 . There was little activity on the bound¬
ary determination during this month. A meeting of
the Commissioners proposed for the twentieth was
postponed on account of lack of a report from Sir
William Johnson. On the twenty-fourth a letter was
received from Nevil Maskelyne, Astronomer Royal, in
which he outlined the methods proposed for the study
of the dimensions of the earth. Also included was art
ephemeris for 1767. Acting on instructions in the let¬

ter, Mason and Dixon sent the astronomical clock to
Philadelphia. The letter of the Astronomer Royal ap¬
pears on pages 279, 280, and 281 of the Journal.

June, 1767 . A report on the rate of the clock was
prepared and directed to the Reverend Nevil Mas-
kelyne and Dr. Morton, Secretary of the Royal Soci¬
ety. A communication was received from Sir William
Johnson stating that the Indians had agreed to the
continuation of the West Line. The weather seems to
have been very hot during the first half of the month.
Mason reported temperatures of 95°F. on the fifth and
sixth and 102°F. on the thirtieth at four in the after¬
noon. The scientists were in Philadelphia on the elev¬
enth and twelfth and prepared instructions to the
Proprietors of both provinces stating that they were
arranging to return for the completion of the West
Line to 5 degrees of longitude west of the Delaware
River. In the middle of the month they sent their
instruments by wagon to the westernmost point pre¬
viously reached in June, 1766. At the same time they
left Brandywine and went to New Town, now Ches¬
tertown, on the Chester River in Maryland to meet
with the Commissioners.

July , 1767 . On the seventh the equipment arrived at
Fort Cumberland and the next day the geodesists were
at the Allegheny frontier, where they had discon¬
tinued the boundary survey a year previous. A new
direction was obtained on the thirteenth and a 10-
minute arc of great circle was begun. At 168 miles 78
chains they reached the top of Savage Mountain,
which Mason records as being the great dividing ridge
of the Allegheny Mountains. Near the middle of the
month the party was joined by fourteen Indian dep¬
uties, i.e., eleven Mohawks and three Onondagas, ac¬
companied by an interpreter, Mr. Hugh Crawford. The
direction was changed on the twenty-fifth at 177 miles
4 chains 45 links and another 10-minute arc of great
circle was begun. No latitude observations were taken
at this time. A small branch running into the Little
Yochio Geni [Youghiogheny] was crossed on the
thirtieth.

August, 1767 . The line was continued. On the sixth
at 188 miles 41 chains 65 links the direction was again
changed, without latitude observations, so as to meet
the parallel at 10 minutes west. At 189 miles 69 chains
the old route of General Braddock leading from Fort
Cumberland to Fort Pitt was crossed, and four days
later on the eleventh the middle of a small island in the
Big Youghiogheny was reached at a distance of 194
miles 28 chains 00 links. The water was reported to be
about a foot deep. On the seventeenth, at a distance of
199 miles 63 chains 68 links from the Post marked
West in Mr. Bryan’s field, the sector, or astronomical
transit, was set up and observations for latitude were
made for seven days. The results showed that they

20

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

were 9.9 seconds or 990 feet north of the parallel and
this distance had to be laid off to the southward to
reach the true boundary. At this station one of the
Mohawk Chiefs, Mr. John Green, and his nephew left
the party to “return to their own country.” On the
twenty-fifth several field assistants were appointed to
work eastward and measure the offsets from the great
circle to the true parallel and open up the “Visto” or
true boundary between Maryland and Pennsylvania
to the point where work had been resumed on the
thirteenth of July. On the twenty-sixth Mason and
Dixon changed direction at the point reached on the
seventeenth and with the main body of the party con¬
tinued westward. On the last day of the month they
reached the 204-mile point and reported that Big
Meadows was north about five miles.

September, 1767 . The line was continued westward.
At a distance of 219 miles 22 chains 25 links the east
bank of Cheat River was reached. The line was re¬
ported to cross the river perpendicularly and the
width was given as about 10 chains. The end of the 10-
minute arc of great circle was reached at 222 miles 24
chains 12 links from the Post marked West. This sta¬
tion was at the “top of a very high steep bank at the
foot of which is the River Monaungahela.” The sector
was set up on the nineteenth and latitude observa¬
tions were made for nine nights. Reduction of the
zenith distances showed the position of the sector to be
3.57 seconds or 357 feet south of the parallel. On the
twenty-eighth Mason and Dixon began to open the
“Visto” eastward on the true parallel in order to ob¬
tain a direction for the next 10-minute arc of great
circle. On the twenty-ninth the party was badly de¬
pleted when twenty-six members deserted. Probably
many were Indian deputies, who would not cross the
Monongahela River for fear of attack by the Shawnee
and Delaware Indians. However, fifteen axmen agreed
to remain on duty to extend the line to the end of the
10-minute arc of great circle. Additional help was
summoned on the thirtieth from nearby Redstone.

October , 1767 . The work proceeded in continuing
the boundary survey westward. A messenger was dis¬
patched to Fort Cumberland to obtain additional
helpers for the survey party and on the seventh the
party was again fully staffed. The extension of the
line continued and crossed an Indian war path at 231
miles 20 chains. This was near a town which had been
burned and most of the inhabitants killed in an In¬
dian massacre in 1755. On the ninth the chief of the
Indians who were acting as deputies declared that the
war path just reached “was the extent of his commis¬
sion from the Chiefs of the Six Nations” and that he
would proceed no farther. All the Indian deputies
now began to protest against any additional extension
of the line, but nevertheless, Mason and Dixon con¬
tinued for nearly 2 more miles and concluded the

boundary demarcation at a distance of 233 miles 17
chains 48 links from the Post marked West. The sector
was set up at a distance of 233 miles 13 chains 68 links
and latitude observations were taken from the elev¬
enth to the eighteenth. These showed that the sector
was 2.23 seconds or 223 feet south of the parallel and
this distance was measured off to the northward to
reach the true boundary. A table of offsets for the last
10-minute arc of great circle was now computed and
the remainder of the month was spent in measuring
such offsets from the arc of great circle actually run.

November , 1767 . The party continued to move east¬
ward and to measure the offsets to the true boundary
from the 10-minute arcs of great circle until the sta¬
tion 199 miles 63 chains 68 links was reached. East¬
ward, beyond this position, temporary markers had
already been placed. Accordingly, there was now one
continuous “Visto” along the boundary, extending
entirely from the northeast corner of Maryland to the
westernmost extent of the survey at 233 miles 17
chains 48 links from the Post marked West. On the
fifth Mr. Hugh Crawford and the Indians and all
helpers except thirteen retained to erect markers in
the line left for their homes. These temporary markers
were huge mounds of earth and stones piled around
the wooden posts which had been placed at the mile
points on the boundary. In the mountains in mid-
November this task was beset by very severe weather
and under such extreme conditions, with twenty-one
inches of snow, the survey helpers declined to con¬
tinue. On the twenty-ninth the demarcation was com¬
plete to Town Hill and the next day Sideling Hill was
reached and the boundary markers, i.e., piles of stone,
had been placed to milepost 135 from the Post marked
West, moving eastward. East of this point cut stone
markers had previously been placed. West of Sideling
Hill they were not used on account of the difficulty of
transportation.

As already stated, the distance to the northeast
corner of Maryland from the Post marked West was 2
miles 79 chains 27 links measured westerly. This gives
the position of the extreme point reached as 230 miles
18 chains 21 links from the northeast corner of Mary¬
land, about 30 miles west of that, long afterward, in
1912, decreed by the U.S. Supreme Court to be the
northeast corner of Maryland. In accordance with
later findings, Lord Baltimore bore half the cost for a
portion of the survey which did not concern his
province—30 miles of demarcation between Pennsyl¬
vania and Virginia, now West Virginia.

December, 1767 . Mason and Dixon were at Cone-
cocheague on the fourth and from that point wrote to
the Commissioners in Annapolis and Philadelphia to
inform them that they would be in Philadelphia on
the fifteenth of the month. The scientists were at
Brandywine on the tenth. The following day they re-

MASON AND DIXON'S SURVEY

21

ceived a letter from Mr. Benjamin Chew, one of the
Commissioners from Pennsylvania, stating that an
official meeting would be held at Christiana Bridge on
the twenty-third. Actually the meeting was held on
the twenty-fourth, twenty-fifth, and twenty-sixth. At
the conclusion of this conference the Commissioners
gave instructions to Mason and Dixon to draw a plan
of the boundary lines which they had marked.

January, 1768 . The plans of the lines of demarca¬
tion were delivered to the Reverend Richard Peters,
Commissioner from Maryland. This concluded the
official responsibilities of Mason and Dixon in the
boundary survey. They were to remain in the colonies
until the following eleventh of September, occupied
in research on the dimensions of the earth for the
Royal Society.

IV. ASTRONOMICAL AND GEODETIC METHODS EMPLOYED BY MASON AND DIXON

1. SCIENTIFIC PROCEDURE OF MASON AND

DIXON IN ESTABLISHING THE PARALLEL

The method employed by Mason and Dixon, now
known as the secant method, basically consists of run¬
ning arcs of great circle which intersect the desired
parallel of latitude at predetermined intercepts. In
the northern hemisphere the arc of the great circle
always lies north of the arc of the parallel. The dis¬
tance from the great circle to the parallel at the mid¬
point of the arc can be calculated by spherical trigo¬
nometry. At intermediate points the offsets from the
great circle are determined by a parabolic variation. The
locus of such points represents a parallel of latitude.

A second type of correction must always be made. It
is never possible to run a long tangent or arc of great
circle without some bearing error. The line inevitably
will deviate to the right or left. This circumstance
necessitates frequent latitude checks, usually at the
end of each arc of great circle where the parallel
should have been intersected. The latitude observa¬
tions show the error in the running of the arc, and the
distances between the intended arc and the arc as
actually run are easily proportioned at desired points
according to straight-line variation.

The latitude agreed upon for the boundary be¬
tween Maryland and Pennsylvania was that of the
“Post marked West," which was on a parallel 15 miles
south of the southernmost point in Philadelphia. The
latitude was found by Mason and Dixon to be
39°43T7.4" (page 103) and in moving west they al¬
ways attempted to hold to this parallel. In the run¬
ning of the boundary the length of the great circle
arcs selected was 10 minutes, now known to equal
11.5151 statute miles.

A fundamental quantity which had to be predeter¬
mined was the bearing on which to run the various 10-
minute arcs of great circle in order to intersect the paral¬
lel at their extremities. This was calculated from spheri¬
cal trigonometry as follows:

Latitude of Post marked West = 39°43T7.4" (page 69)
Co-Latitude of

Post marked West = 50°16'42.6" (page 69)

Length of

semi-arc of great circle = 0°05'00.0"

The above data specify a right spherical triangle with
sides as follows:

a. Extending from the pole of the earth to the inter¬
section point of a circle of latitude with a 10-
minute arc of great circle (50°16'42.6")

b. Extending from the pole of the earth to the mid¬
point of a 10-minute arc of great circle

c. The semi-arc of great circle = 0°05'00"

From the trigonometry of the right spherical triangle
it is seen that

tan 0°05'00" .00145444

Cosine Bearing = tan 50°]6'42.6" = 1.20358657

= .00120842 (0° - 04' - 09")

Bearing = N89°55'51"W

This shows that the deflection angle to be turned off
at the extremity of each chord or 10-minute arc was
0°08'18".

These changes in direction at times were accom¬
plished by astronomical procedures, but it appears
that the angle was frequently turned off from the
plate of the transit or was established by the method
of offsets from the tangent.

2. STARS OBSERVED

The major portion of the astronomical work con¬
sisted of latitude observations to furnish control for
the boundary demarcation between Pennsylvania and
Maryland. For this purpose stars of low zenith dis¬
tance were employed. Other work involved azimuth
determinations such as were necessary to ascertain the
direction of the Tangent Line at the Middle Point in
connection with the subsequent study of the length of
a degree of latitude for the Royal Society. Azimuth
settings also were required for control of the direc¬
tions of the numerous 10-minute chords of great circle
from which the offsets to the boundary were measured.

22

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

In addition, it was necessary to establish the meridian
in running the North Line and the line of 15 miles
length between the stations at Mr. John Harland’s
and Mr. Alexander Bryan’s. At other times observa¬
tions were required in connection with the standardi¬
zation of clocks for the Royal Society and the checking
of occupations.

Following are two lists of stars used by Mason and
Dixon for the purposes indicated:

Sfaurs for Latitude

Gamma Andromedae (Almach)

Beta Aurigae (Menkalinan)

Gamma Cygni (Sadr)

Delta Cygni
Alpha Lyrae (Vega)

Alpha Persei (Marfak)

Beta Persei (Algol)

Alpha Aurigae (Capella)

Alpha Geminorum (Castor)

Time Stars and Azimuth Stars

Alpha Andromedae (Alpheratz)

Beta Andromedae (Mirach)

Alpha Arietis (Hamal)

Alpha Coronae Borealis (Alphecca)

Beta Draconis
Gamma Draconis
Gamma Geminorum
Alpha Leonis (Regulus)

Beta Leonis (Denebola)

Alpha Ophiuchi (Rasalhague)

Alpha Orionis (Betelgeuse)

Eta Tauri (Alcyone)

Beta Ursae Majoris (Merak)

Epsilon Ursae Majoris (Alioth)

Beta Ursae Minoris (Kochab)

Alpha Tauri (Aldebaran)

Alpha Scorpii (Antares)

Alpha Bootis (Arcturus)

Alpha Ursae Minoris (Polaris)

Beta Geminorum (Pollux)

Alpha Canis Minoris (Procyon)

Alpha Canis Majoris (Sirius)

Alpha Virginis (Spica)

3. OBSERVATIONS AND THEIR REDUCTION

In the latitude calculations the usual formula was
followed, i.e.:

z ~ <j> ~ B

The declinations, 8, were taken from a then recent
star catalogue by the Astronomer Royal, James Bradley,
whose assistant Charles Mason had been from 1756 to
1760. Corrections to observed star positions were made
for nutation, precession, annual aberration, and refrac¬

tion. Proper motion corrections do not appear but as
the star positions were of current date, this item proba¬
bly was not important. Annual parallax had not yet been
evaluated and hence does not appear in the list of cor¬
rections. Its influence is usually small.

When the survey line crossed a river, triangula¬
tion procedures were used to determine the unknown
distance. Oblique triangles were used at times, an un¬
usual practice which must be attributed to lack of a dear
vista along the lines desired for sight. The angles were
taken with a Hadley quadrant Distances were mea¬
sured horizontally and were recorded in miles, chains,
and links.

In azimuth observations and in establishing the
meridian, the method of taking stars at equal alti¬
tudes at premeridian and postmeridian transits was
employed. Other methods were those of offsets from
the tangent and the precalculation of the time at
which a star would be on a desired azimuth.

4. THE SOUTHERN BORDER OF DELAWARE

The semi-Transpeninsular Line or southern border
of Delaware was spedfied to extend from Cape Hen-
lopen west to a point midway between the Atlantic
Ocean and the Chesapeake Bay, Le., the Middle
Point. But as there is no record of astronomical con¬
trol for latitude, it would appear that what the colo¬
nial surveyors did was actually to prolong a tangent
which would have been an arc of a great circle. Eight
monuments were placed. This was not the work of
Mason and Dixon, having been accomplished by local
surveyors in 1751.

5. THE FIVE LINES OF MASON AND DIXON

The border demarcations of the two geodesists may be
summarized as follows:

a. The West Line, or border between Pennsylvania
on the north and Maryland and Virginia (now
West Virginia) on the south, which extends 230
miles 18 chains 21 links west from the northeast
corner of Maryland.

b. The East Line, which extends as a secant through
the northern portion of Delaware. The length from
the northeast corner of Maryland to Delaware Bay
is 14 miles 20 chains 15 links. This distance was
desired in order to ascertain when 5 degrees of
longitude west of Delaware Bay had been reached.
The line was of no importance to Maryland
though that colony sustained half of the expense
of running it.

c. The Tangent Line, which extends from the Middle
Point to the Tangent Point for a distance of
6558.31 chains or 81 miles 78 chains 31 links
(page 269).

d. The Arc Line, which follows a part of the curve
of the circle of 12 miles radius around New Castle
courthouse. The subtended secant is 1.451 miles.

ASTRONOMICAL AND GEODETIC METHODS EMPLOYED 23

Fig. 5. Surveyors’ diagram illustrating location of the Tangent Line (Journal, page 24).

24

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

This gives the length of the Arc Line as 1.452
miles.

e. The North Line, which is the distance from the
Tangent Point to the northeast corner of Mary¬
land less that portion of the line which is a secant
to the circle of 12 miles radius. This equals 5.019
miles less 1.451 miles = 3.568 miles.

Some monuments were reset in 1849 with slight al¬
terations in distance.

6. CORRECTIONS TO THE TANGENT LINE

The Tangent Line as established by colonial sur¬
veyors was somewhat imperfect. It is believed that in
general the procedure employed by Mason and Dixon
in ultimately obtaining a tangency was to determine
the error at the Tangent Point, to reset the point
accordingly, and to move all other markers on the line
by a distance proportional to their distance from the
Middle Point. However, statements in the Journal on
this matter are obscure.

7. INSTRUMENTS AND EQUIPMENT USED

The principal item of equipment was an astronomi¬
cal transit or “sector,” as it was called. It is believed to
have been similar to the zenith telescopes used until
recent years by the U.S. Coast and Geodetic Survey.

The name evidently arose from the fact that the grad¬
uated arc for the reading of zenith distances actually
was a sector of a circle. A micrometer made observa¬
tions possible to a hundredth of a second of arc.
Troughton and Simms of London were producing ex¬
cellent instruments of this kind in 1849.

Other equipment consisted of a direction transit, a
navigator's quadrant, chains of 66 feet (100 links per
chain), an astronomical clock, wooden rods of 16.5 feet
with spirit level, and other rods of 10 feet length. Also
included were an up-to-date star catalogue by Dr.
Bradley, adequate tables for astronomical corrections
to observations, and seven-place logarithmic tables for
numbers and sines and tangents. To these items may
be added the other more common articles required by
surveyors, camp equipment for thirty-nine men, and
horses and wagons for transportation of personnel and
gear.

At times Mason and Dixon worked under unusual
and adverse circumstances, for example, on Christmas
Day, and in snow two feet deep, and in temperatures
as low as 22° below zero F. Their task was carried out
in frontier country without benefit of modem meth¬
ods and conveniences. But, after two hundred years,
checks by the most refined methods of geodesy attest to
the mathematical excellence of their accomplishment.

V. DETERMINATION OF THE LENGTH OF A DEGREE OF LATITUDE

FOR THE ROYAL SOCIETY

The geometry involved in a preliminary evaluation of
the circumference of the earth is indeed quite simple.
Assuming a nearly spherical figure, it is obvious that the
circumference may be approximately calculated from a
knowledge of the length of one degree of latitude. If
such a distance be represented by d, then the circum¬
ference C will be 360 d. To evaluate d, all one has to do
is to measure the distance between two points on a
meridional arc and obtain latitude observations at each
point. Then d is the quotient of the total distance divided
by the difference in latitude. The latitude follows from
the well-known equation,

where 5 = zenith distance of a star at upper meridian
transit

h = declination of the star

<£ = latitude of the point of observation.

Modern geodetic work may be considered to have
started in 1617 with Willebrord Snell, also famed for
having discovered the sine law of refraction. His
method was to determine the length of the arc of a
meridian by triangulation, but ultimately he reached

a value which was about 3 per cent too small. Other
similar attempts were made in the seventeenth and
eighteenth centuries in France, Lapland, Peru, and
South Africa.

A very desirable requirement in this type of geo¬
detic research is terrain level enough to permit laying
out a truly horizontal line. Mason and Dixon, having
observed the smooth topography of what we now call
the Delmarva Peninsula, in 1764 proposed to the
Royal Society that it sponsor the measurement there
of an arc of the meridian. The proposal met with
enthusiastic response. Much germane correspondence
may be seen in the Journal of Mason and Dixon,
pages 209-221. Their work on this problem was prin¬
cipally accomplished after the completion of the
boundary survey, but some progress was made during
the winter furlough and in periods when instructions
were awaited from the Commissioners.

Elaborate instruments were shipped by the Royal
Society to be used in the research but as mentioned on
page 213 of the Journal the equipment was lost with
the missing ship “Egdon.” However, Mason decided
that the instruments which had been used in the
boundary survey could be depended upon to give sat-

DETERMINATION OF THE LENGTH OF A DEGREE OF LATITUDE

25

isfactory results. The Penns and Lord Baltimore made
available additional equipment of their own. Very
detailed instructions sent over by Nevil Maskelyne,
Astronomer Royal, appear on pages 213-218 of the
Journal.

The procedure followed was to determine very pre¬
cisely the latitude of the Middle Point, i.e., the south¬
west corner of Delaware, and also that of the north end
of the 15-mile line where previous observations had been
made in January, 1764, in the yard of Mr. John Harland
at the Forks of the Brandywine. The difference in lati¬
tude between these two points would give the length in
degrees of an arc along a meridian between the two
circles of latitude on which they lie. In addition to the
astronomical observations, it was necessary to obtain the
distance in feet between the two parallels. This con¬
sisted of three components:

1. The 15-mile line from Mr. Harland’s to Mr.
Bryan’s.

2. The North Line from the West Line to the Tan¬
gent Point.

3. The meridional component of the Tangent Line
from the Tangent Point to the Middle Point.
(The bearing of the line at the Middle Point is
N3°43 / 30"W by astronomical observations.)
(page 267)

Mason lists the following data as a basis for the neces¬
sary calculations:

1. Based on the entire line from Mr. Harland’s to
the Middle Point:

a. Latitude at Mr. Harland’s at Brandywine

= 39°56T9" (page 267)

b . Latitude of the Middle Point

= 38°27'34" (page 267)

c. Latitude at the mid-point of the arc

= 39°11'56.5"

d . Difference in latitude

= 1°28'44.99" = 5324.99" = 1.47916389 de¬
grees (page 269)

e . Distance between the points

= 8132.933 chains (page 271)

f. Length of a degree of latitude

= 8132.933 chains divided by 1.47916389
degrees

= 5498.331 chains = 68 miles 58 chains 33
links (page 271)

= 68.7291 miles

The modern value based on the Clarke Spheroid of
1866 is 68.9833 miles (one second of arc = 30.838
meters). One meter = 39.370432 inches. Mason and
Dixon’s error was therefore 0.2542 mile, 0.368 per cent
of the correct value.

2. Based on the line from Mr. Bryan’s to the Middle
Point:

a. Latitude at Mr. Bryan’s

= 39°43'23.45" (page 272)

b. Latitude at the Middle Point

= 38°27'34" (page 267)

c . Latitude at the mid-point of the arc

= 39°05'28.72"

d. Difference in latitude

= 1°15'49.45" = 4549.45" = 1.2637361Lde-
grees (page 272)

e . Distance between the two points

= 6956 chains 76 links (page 272)

/. Length of a degree of latitude

= 6956.76 chains divided by 1.26373611 de¬
grees

= 68 miles 64 chains 91 links (page 272)

= 68.8114 miles

The modern value based on the Clarke Spheroid of
1866 is 68.9810 miles (one second of arc =30.837
meters). Mason and Dixon’s error is 0.1696 mile, 0.246
per cent of the correct value.

The two arcs are sufficiently close in mid-point lati¬
tude for an average to appear justifiable. The mean
value would be determined by 68.7291 and 68.8114, or
68.7702 miles. Assuming a spherical earth, the circum¬
ference would be 24757 miles. The radius then be¬
comes 24757-r 2ir = 3940 miles. Based on the Clarke
Spheroid of 1866, the equatorial radius is 3963.34
miles and the polar radius is 3949.99 miles. Using the
equatorial radius twice, the mean radius is 3959 miles.
The error is seen to be 19 miles in radius or 0.48 per
cent. 1

Cavendish (1731-1810) reviewed the results of
Mason and Dixon in association with the topography
of the Atlantic Seaboard and Allegheny Mountains.
He concluded that the excess of attraction from the
mountains and the deficiency beyond the continental
shelf could have produced a significant effect on the
latitude observations. An examination of the behavior
of the geoid in the concerned area discloses a very
erratic condition. 2 To extrapolate known station er¬
rors for values at the three concerned points would
not appear in consonance with the scientific approach
and therefore will not be attempted. It would be nec¬
essary to connect the three stations occupied by Mason
and Dixon with the North American Datum and as¬
certain the anomaly in latitude at each point.

_ At the time of Mason and Dixon the ellipticity of
the earth was known (see correspondence from Mas¬
kelyne, Journal, page 218) but had not been mathe¬
matically evaluated. The basic information desired at
that epoch was the circumference of the earth based

1 The Figure of the Earth, Bulletin 78 of National Research
Council,

2 Deflections of the Vertical in the United States (Special
Publication No. 229, U.S. Coast and Geodetic Survey).

LrTlfSft Htfh

Bail U*n ore o

LATITUDE
rvfrs meao'u red
^ for the
Royal S o cicW

4 y

Cba:jtfa*rcn-
olJ? re:D i\ro n .

SOURCES AND TECHNICAL REFERENCES

27

on the assumption of a spherical figure. The refine¬
ments of Bessel, Clarke, and Hayford had to be
awaited.

In all research, progress is by slow, successive ad¬
vances, each' discovery contributing its part to our pre¬

cious heritage of knowledge. In the domain of world
geodesy the names of Mason and Dixon will always be
found in the roll of great scientists who with zeal and
patience sought to advance knowledge of the figure of
our earth.

VI. SOURCES AND TECHNICAL REFERENCES

Bayliff, W. H. 1959. The Maryland-Pennsylvania and the
Maryland-Delaware Boundaries. Bulletin No. 4 (2nd ed.),
Maryland Board of Natural Resources (Annapolis, Md.).

Burchard, Edward L., and Edward B. Mathews. 1908-1909.
“Manuscripts and Publications Relating to the Mason and
Dixon Line and Other lines in Pennsylvania, Maryland, and
the Virginias.” In: Report of the Resurvey of the Maryland-
Pennsylvania Boundary, Secretary of Internal Affairs, Harris¬
burg, Pa., and Maryland Geological Survey, Special Publica¬
tion VII (Baltimore, Md., Johns Hopkins Press).

Cope, Thomas D. 1939. “The Stargazer's Stone.” Pennsylvania
History 6: pp. 205-220.

- 1944. “The Apprentice Years of Mason and Dixon.” Ibid.

11: pp. 155-170.

- 1948. “Collecting Source Material about Charles Mason

and Jeremiah Dixon.” Proc. Amer. Philos, Soc. 92: pp. 111-
114.

- 1949. “Mason and Dixon, English Men of Science.”

Delaware Notes (University of Delaware, Newark, Del., 22nd
ser.), pp. 13-32.

-1951. “Some Contacts of Benjamin Franklin with Mason

and Dixon and their Work.” Proc, Amer. Philos. Soc. 95; pp.
232-238.

- 1953. “The Jersey Quadrant Used in Pennsylvania.”

Ibid. 97: pp. 565-571.

- 1955. “Some Local Scholars who Counseled the Pro¬
prietors and their Commissioners during the Border Surveys
of the 1760’s.” Ibid. 99: pp. 268-276.

- 1956. “When the Stars Interrupted the Running of a

Meridian Line Northward up the Delmarva Peninsula.” Ibid.
100: pp. 557-566.

Cope, Thomas D., and H. W. Robinson. 1952. “The Astro¬
nomical Manuscripts which Charles Mason Gave to Provost
the Reverend John Ewing during October 1786.” Ibid. 96: pp.
417-423.

Cope, Thomas D., and H. W. Robinson. 1954. “When the
Maryland-Pennsylvania Boundary Survey Changed from a
Political and Legal Study into a Scientific and Technological
Project.” Ibid. 98: pp. 432-441.

Cummins, Hubertis M. 1962. The Mason and Dixon Line,
Story for a Bicentenary, 1763-1963 (Harrisburg, Pa. Com¬
monwealth of Pennsylvania, Department of Internal Affairs).

Douglas, Edward M. 1932. “Boundaries, Areas, Geographic
Centers, and Altitudes of the United States and the Several
States.” U.S. Geological Survey, Bulletin No. 817 (Washing¬
ton, Government Printing Office).

Duerksen, J. A. 1941. Deflections of the Vertical in the United
States. U.S. Coast and Geodetic Survey, Special Publication
No. 229 (U.S. Department of Commerce, Washington, D.C.).

Dwight, H. D. 1926. “The Mason and Dixon Line.” Yale Re¬
view, n.s., 15: pp. 687-702.

Footner, Hulbert. 1944. Rivers of the Eastern Shore (New
York, Farrar and Rinehart).

Hoskinson, Albert J., and J. A. Duerksen. 1947. “Determin¬
ation of Longitude, Latitude, and Azimuth.” Manual of Geo¬
detic Astronomy, U.S. Coast and Geodetic Survey, Special
Publication No. 237 (Washington, Government Printing Of¬
fice).

Hosmer, George L. 1930. Geodesy (2nd ed., New York, Wiley).

Lambert, W. D. ca. 1947. “Two Geodesists of the Eighteenth
Century.” Manuscript article in possession of A. Hughlett
Mason.

Mason, Charles. 1768. “Observations for Determining the
Length of a Degree of Latitude in the Provinces of Maryland
and Pennsylvania, in North America.” Phil. Trans. Royal
Society of London 58: pp. 274-328.

Mason, A. Hughlett, and William F. Swindler. 1964.
“Mason and Dixon, Their Line and Its Legend.” American
Heritage 15: pp. 22-29, 93-96.

Rudy, G. T., et al. 1931. Physics of the Earth. II, The Figure
of the Earth (Washington, D.C., National Research Council).

THE JOURNAL OF

CHARLES MASON AND JEREMIAH DIXON
1763-1768

The numbers, beginning with 25, appearing in the
right-hand margin indicate the last line on the corre¬
sponding pages in the Mason and Dixon Journal.

Redrawn versions of the freehand representations of
Charles Mason appear at the end of the transcript. The
figure numbers agree with the page numbers in the
Journal.

1763

November

15 Arrived at Philadelphia

16 Attended a meeting of the Commissioners appointed by the
Proprietors of Pennsylvania to settle the boundaries of the Province

17 Wrote to his Excellency Horatio Sharpe, Esquire, Governor of
Maryland, signifying our arrival at Philadelphia.

22 Landed the Instruments

25 Set up the Sector and found it had not received any damage
28 Set up the Transit and found it had not received any damage
30 The Commissioners appointed by Lord Baltimore to settle the
Boundaries of Maryland came to Philadelphia

December

1 Attended a meeting of the Commissioners of both Provinces,
and set up the Compound Instrument of Lord Baltimore's

2 Attended a meeting of the Commissioners

3 Attended a meeting of the Commissioners

5 Attended a meeting of the Commissioners and directed a carpenter to build an observatory
near the point settled by the Commissioners to be the South end of the

City of Philadelphia

6 Set up a Sector brought by the Commissioners from Maryland

and found the nonius (vernier) would not touch the middle part of the arch.

Was sworn before the Commissioners.

7 Attended the Commissioners

8 Carried some of our Instruments in to the Observatory

9 Attended the Commissioners and received our Instructions
10-13 incl. Got the Observatory finished and fixed up our Instruments

proper for observing.

14-15 incl. Rain and Snow

31

1763

December

16 Brought the Instrument into the Meridian by making several

stars pass along the horizontal wire in the middle of the Telescope
The method pursued in doing of this is as follows:

Let HO be the horizontal, and NS be the
vertical wire. Then we bring a Northern

star (one as far north of the zenith as the limit of the Arch) to

the Horizontal wire at a, and it will describe

the arch of a circle as ab c, (the Telescope inverting).

If a^p be apparently equal to £c, it is truly

in the Meridian, if not equal, we proceed by trial until they are equal;
which may be done with four or five stars to great exactitude as we
find by comparing the time of the stars passing the wire NS, with the
time they transit the Meridian as found by Equal Altitudes

17 Cloudy

18 Cloudy. Sunday.

19 Plane of the Sector facing the EAST

Star

Magnitudes

Star Names

Right

Ascension

Nearest point
on the Sector

Delta Persei

m

o

7

i

5 -

0.2

Capella

4

59

5

50-

Chi Ursae Majoris

8

5 +

0.1

Alpha Lyrae

18

29

1

20 +

2.2

Gamma Androm.

1

49

15-

2.0

Beta Persei

2

53

0

5 +

Delta Persei

3

26

7

5-

0.2

Capella

4

59

5

50-

2.0

Beta Aurigae

5

42

4

55 +

Alpha Cygni

2

34

4

30+

Gamma Andromedae

1

15-

Beta Persei

0

5 +

Delta Persei

7

5-

Capella

5

50 -

Beta Aurigae

4

55 +

Castor

7

19

7

35-

Revolutions and

Difference

Apparent

Seconds on the

Zenith

Micrometer

Distance

R

it

R

1!

o

i

ii

10

20

0

41. 5

7

4

18. 5

N

11

9. 5

2

39. 5

3

6. 5

5

47

5

46

5

26. 5

2

45. 2

8

7

2

33

9

29. 5

2

17.5

1

22

1.5

11

47

7

32

0

9.0

1

14

7

41

10

16. 5

0

25.0

0

5

9

43. 5

8

43

0

43. 5

7

4

9

34. 5

16

24. 5

3

0.0

5

47

9

24. 5

Fig.

5

40.5

2

29. 5

4

57

13.5

26

3

11

8

36

0

4

30

16.0

N *

8

20

7

48 +

0

10.7

1

14

49.3

N

8

7

8

33 +

0

26. 3

0

5

26.3

N

8

7

6

45. 5

0

44. 5

7

4

15. 5

N

7

38

7

37. 5

3

5. 5

5

47

18. 5

N

10

43

11

14. 5

2

25. 2

4

57

9. 2

N

8

41 +

8

9 -

46. 2

7

33

21.8

S

6

14. 5

* very faint

32

1763

December

Star

Star Names Right

Nearest point

Revolutions and

Difference

Apparent

Magnitude

Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance

h m

o

i

R

ii

R

it

o

i

ii

22

Alpha Lyrae

1

20 4

7

21.5

2

21.5

1

22

5.5

S

9

43

Alpha Cygni

4

30 +

11

48

0

15.7

4

30

15.7

11

32 +

Capella

5

50 -

10

43

3

0.5

5

47

23. 5

13

43.5

Castor-

7

35 -

14

33 -

1

47.7

7

33

20.3

12

37

Chi Ursae Majoris

8

5 +

7

15

2

47.3

8

7

31.3

4

19.75

23

Cloudy'

24i

Cloudy

25

Sunday

Gamma Andromedae

1

15 -

5

45.5

0

10. 5

1

14

49.5

N

6

4

Beta Persei

0

5 +

6

21

0

23.7

0

5

23.7

5

49

Delta Persei

7

5 -

7

15, 5

0

45. 5

7

4

14. 5

8

9

0.2

Capella

5

50-

7

36

3

0.0

5

47

24. 0

10

36

2.0

Beta Aurigae

4

55 +

10

17

2

35.0

4

57

19.0

7

34

1.6

Castor

7

35-

7

48

1

49.7

7

33

18.3

5

50

Equal Altitudes of Beta Aurigae on the Transit Instrument

Time of Watch

Passed the Meridian

h m s h

m

s

h

m

s

4i 23 15

—

24 22 6

59

16

5

41

49

25 35 7

0

25

5

41

50

Hence Beta Aurigae passed the Meridian at 5h 41m 49.

5 s by the watch and it

was observed to pass the vertical or meridian wire in the Sector at

5h 41m 50s by the watch

26

Cloudy

27

0. 1

Alpha Lyrae 18 29

1

20 +

4

3

2

22.0

1

22

6.0

S

6

25

2,2:

Gamma Andromedae

1

15 -

4

17

0

11.7

1

14

48. 3

N

4

29 -

O.fc

Beta Persei

0

5 +

4

19. 5

0

26.5

0

5

26. 5

N

3

45

1.9

Alpha Persei

9

5 -

3

31 -

1

34.6

9

3

33.4

N

5

13 +

Delta Persei

7

5 -

5

16

0

42.3

7

4

17.7

N

6

6 +

0. 2

Capella

5

50 -

5

22.5

3

3.5

5

47

20. 5

N

8

26

2.0

Beta Aurigae

4

55 +

8

23 -

2

29.7

4

57

13.7

N

5

45

1.6

Castor

7

35 -

6

20 +

1

48.3

7

33

19.7

S

24

* faint

33

1763

December

Star Star Names

Magnitude

Alpha Lyrae

Nearest Point Revolutions and Difference Apparent
" ' ’* Zenith

Distance (Plane East)

X\ r ,f

20 +

28

29

30

0.2

2.0

1.6

Cloudy

0 . 1

Right ___ _ _

Ascension on the Sector Seconds on the

Micrometer

h m ° ’ R M

18 29 l 20+ 11 5.5

13 26-

After Alpha Lyrae passed the Meridian we turned the Plane of the Sector
and brought it in the Meridian by Stars of the Evening, then took the following
Plane of the Sector facing the WEST

R

2

20,2

22

4.2

1.3

31

1764
January
1 Sun.

Capella 4 59

Beta Aurigae 5 43

Castor

Chi Ursae Majoris

Alpha Lyrae 18 29

Alpha Cygni

Gamma Andromedae

Beta Persei

Alpha Persei

Delta Persei

Capella

Beta Aurigae

Castor

Chi Ursae Majoris

Equal Altitudes of Capella

5

4

7

8

4
1
0
9

5
4

7

8

Time by the Watch
h m s h

m

s

3 50

32 5

55

41

51

35

56

58

52

54

58

11

Alpha Lyrae
Gamma Andromedae

Gamma Andromedae
Beta Persei
Capella
Beta Aurigae
Castor

Chi Ursae Majoris

50-

55+

35-

5+

20 +

30+

15-

5+

5-

5-

50-

55+

35-

5+

6

3

4

7
6

8

4
7

3

1

6

6

6

6

5

6
6
5
3
3
3
0
0
3
7
9
9

13

24,5

32-

2

44.8

5

47

31.2

13

0.5

2

39.5

4

57

23,5

46-

47.5

2

1.7

7

33

14.3

46.5

51-

3

4.2

8

7

40.2

36-

22

2

13.7

1

21

57.7 S

22-

35

0

13.3

4

30

13.3 N

16.5

11-

0

5.8

1

14

54.2 N

47+

26. 5

0

31.2

0

5

31.2 N

28

7+

Not

completed

44+

4. 5

0

39. 8

7

4

20.2 N

42.3

45

2

49.3

5

47

26.7 N

41

28. 5

2

39.5

4

57

23.5 N

43.5

43+

1

51. 8

7

33

16.2 S

47.4

0.0

3

4.6

8

7

40.6

29

Hence Capella passed the Meridian of the Transit
Instrument at 4h 54m 18s and it was observed to
pass the Vertical Wire of the Sector at 4h 54m 7s

1

20+

11

45

2

17

1

22

1.0

9

28

1

15-

6

3

0

6.5

1

14

53.5

5

48. 5

1

15-

6

19.7

0

6.4

1

14

53.6 N

6

13.3

0

5+

7

22

0

31.5

0

5

31.5

8

1.5

5

50-

11

28

2

45.0

5

47

31.0

8

35

4

55+

8

26+

2

38.7

4

57

22.7

11

13

7

35-

11

4

1

51.0

7

33

17.0

13

3

8

5+

12

41

3

3.7

8

7

39.7

15

45-

34

1764

January

Star

Magnitude

2

3

4

Star Names

Right

Nearest point

Revolutions and

Difference

Apparent

Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance (Plane West)

h m

0

i

R

ti

R

»t

o

1

ii

Gamma Andromedae

1

15-

11

33. 5

0

6.5

1

14

53.5

11

27

Beta Persei

0

5+

10

27.5

0

30.0

0

5

30.0

11

5. 5

Alpha Persei

9

5-

13

47

1

27. 0

9

3

41.0

12

20

Delta Persei

7

5-

13

22+

0

39.3

7

4

20. 7

12

35

Capella

5

50-

13

5

2

45.5

5

47

30. 5

10

11.5

Beta Aurigae

4

55+

10

39. 5

2

38. 5

4

57

22.5

13

26

Castor

7

35-

11

39. 5

1

50. 5

7

33

17.5

13

38

Alpha Cygni

4

30+

8

7. 5

0

14.0

4

30

14. 0*

8

21.5

Alpha Lyrae

1

20+

8

29

2

17.5

1

22

1.5

6

11.5

30

For the Southing of the Southernmost point of the City of Philadelphia from the Sector in the
Observatory. (NOTE: Angle notation supplied by editor)
log 10.3 = 1.01284
log 13.7 * 1. 13672

Difference 9. 87612-10 = log cos Angle HBC
Angle HBC = 41° 15'

Angle BHC = 180°- 2(41°15') = 97030'

Angle AHF = 97030' - 90O00' = 7°30'

AP = 45.55 sin 7°30'
log 45.6 = 10.65896-10

log sin 7°30'= 9. 11570-10
log AP = 9.77466-10

AP = 5.95

SH = 31.2

37.15 = Yards the point is South of the Sector

= 1.1" of latitude Figure

In the above PH is on the South side of Cedar Street, P the point fixed on by the Commissioners
to be the Southernmost point of the City of Philadelphia. S represents the Sector in the Observatory.
(PA is the meridional distance that) H is South from the Sector. 31

very faint

35

Apparent Zenith Distance, Plane of the Sector EAST

Cn>

ON

1763

December

19

20
21
22

25 (Sun.)

27

Mean (Dec. 23)

Aberration

Deviation

Refraction

Mean Zenith Distance
Precession to Jan. 1,1764
Corrected Z. D.
Declination (Dr. Bradley)
Latitude (Plane East)

1763

December

Gamns a Andromodac

Beta Perse;;

□

■

m

G

p

n

1

14

51* 0

0

5

25.0

1

14

4D+ 3

0

5

EG. 3

1

14

49. 5

0

5

23.7

1

14

4E3, 3

0

5

26, 5

l

14

49.5

0

5

25.1

-ll.fi

- 0,5

- 3 t 1

-5*5

+ u

4 0*1

1

14

3G. a

Q

5

10.5

+ 0.4

+ 0. 4

i

11

36.4

D

5

tO. 9

28

30

1

14

54. 2

31

1

14

53. 5

1764 1 Jan. (Sun. )

1

14

53.6

2

1

14

53.5

3

4

Mean, 1 Jan.

Abberation

Deviation

Refraction

Mean Zenith Distance
Declination (Dr. Bradley)
Latitude (Plane West)
Latitude (Plane East)
Mean Latitude

Mean of all Latitudes
Mean Z. D. (East)
Mean Z. D. (West)
True Z. D. at Sector
Point South of Sector
True Z. D. 1 Jan. 1764

14

14

53.7
-11.5
- 3.1
+ 1.4
40.5

14 36.4

14 40.5

14 38.45

+ 1. 1
14 39.55

Alpha Pcrsiei Delta Peraci
o o'"

C&pella

Beta AurLjjae

Cantor

35.5

15.5

33*4

4 14.5

4 17.7

33.4
-10*7
- 6.0
+10.5

37. 2
4 - { 1.2

27.4

7

47

4 1G.05

- 9.3

- fi.S

+ B.3

4 IS. 5
+ 0*3
4 8.B

0 33.7

39 56 31, 2

Plane of the Sector WEST

31.2

4 20.2

5 31.5

5 30.0

41.0

30.9

- 9.7

- 5.5

+ 0.1

15.8

41.0
- 11.0
- 6.0
+ 10.5
34.5

7

4

20,

.7

7

4

20,

► 5

- 9,

.9

- 6.

,5

+ 8.

, 3

7

4

12.

,4

47

0

40.

,0

39

56

27.

,6

39

56

31.

2

39

56

29.

4

32.

4

31.

2

29.

6

28.

4

0 5 10.9

0 5 15.8

0 5 13.35

_ + 1.1

0

14.45 9

27.4

34.5
30.95

+ 1.1

32.05

39 56 30,2 - Latitude of the observatory

4 8.8

4 12.4

4 10.6

+ 1.1

4

5 47 17.2 4 57 8.9

5 47 23.9 4 57 17.2

5 47 20. 55 4 57 13.05

_ ± 1.1 + 1.1

H.7 5 47 21.65 4 57 14. 15

0

i

d

i

fr

Q

i

ii

5

47

24 T 0

4

57

13* 5

_ _

-- _

_ , _ _ _

-■

-■

—

7

33

21. 3

5

47

23. E

>-

—

- —--

7

13

20*3

5

17

24. 0

-

—

7

33

13.3

5

47

20.5

4

57

13* 7

7

33

19* 7

□

47

23.0

4

57

13. G

7

33

20. 0

- 3*9

- U

- 3 r G

- fl. 7

- D T 2

+ 0.2

4 G. 7

+ 5, B

+ e r s

E

47

17. 1

1

57

0.9

7

33

34 T 4

+ 0 S 1

0.0

+ 0*2

5

47

17.2

4

57

8.9

7

33

34.5

45

43

52. 9

44

53

44. 0

32

22

5G. 7

39

56

35. 7

39

55

35. 9

39

31.3

5

47

31. 2

4

57

23. 5

7

33

14.3

- -

---■

—

4

57

23.5

7

33

16.2

5

47

31. 0

4

57

22. 7

7

33

17.0

5

47

30. 5

4

57

22.5

7

33

17.5

5

47

30.9

4

57

23.0

7

33

16.2

- 5.0

- 2.4

- 3. 1

- 8.7

-9.2

+ 9.2

I- 6.7

+ 5.8

+ 8.8

5

47

23.9

4

57

17.2

7

33

31. 1

45

43

53.0

44

53

44. 2

32

22

56.8

39

56

29. 1

39

56

27.0

39

56

27.9

39

56

35.8

39

56

35. 3

39

56

31.3

39

56

32.4

39

56

31. 2

39

56

29.6

7 33
7 33
7 33

34.6
31. 1
32.8
- 1.1

7 33 31.7

32

Date

Alpha Lyrae

Plane EAST

1763

o

i

n

The mean day of the observations in all the stars is

23rd of December except Alpha Persei which is
the 27th, and Alpha Lyrae which is the 26th, etc.

Plane WEST

The mean day for Alpha Lyrae is the second of

1

22

5.5

January, all the others is the first.

1

22

6.0

1

22

4.2

The small numbers in the line * are the precessions

1

22

5.2

from December 23 to January 1; they are not used

+ 0. 1

in bringing out the Latitude, etc., that being accounted

- 9.4
+ 1.5

for in the Stars' Declinations.

T~

21

57.4

l

21

57.4 =

Mean Zenith Distance the first of January

38

34

34.0

39

56

31.4

From the foregoing the mean of the Latitudes given by the
five different Stars is at the Observatory equal to 39° 56' 30". 2

The Southernmost point of the City of Philadelphia

Dec.

is south of this point 0 1.1

31

22

1.0

True Latitude of the Southernmost point

1764

of the City of Philadelphia equals 39° 56' 29". 1 North

Jan.

4

22

1.5

Or the Latitude thus determined and given in to the Proprietors

Mean

2 Jan.

1 22

1.2

- 2.0
- 9.4
* + 1.5

1

21

51.3

38

34

34.0

56

25„3

56

31.4

39"

56

28.4

1

21

57.4

1

21

51.3

1

21

54.35

- 1.1

T~

21

53.25

True Zenith Distance

Delta Persei

Cape 11a

Beta Aurigae

Castor

AHjatoca Lyrae

of the Star the 1st Jan. 1764

Their Declinations according to

7°

4' 11". 6

5°

47' 21". 6

4°

57* 14". 2

70 33*

31". 6

1® 21" S3". 2

Dr. Bradley, 1st Jan. 1764

47°

O' 40". 0

45

43 53 .0

44

53 44 .2

32 22

56 .8

38 34 34.0

Latitude of the South point
of Philadelphia by the different stars

39

56 28 .4

39

56 31 .4

39

56 30 *.0

39 56

28 .4

39 56 27 .2

28.4

31.4
30.0

28.4
27.2

39° 56' 29VI as above

37

cri cn

Gentlemen:

Philadelphia 7th January 1764

I hope you have pleased yourselves with good horses
and an agreeable companion.

The Temporary Line went through the Township of Darby
and the plantation of Thomas Lyeth - through Springfield at Samuel
Lewis’ - through Providence Township at John Worral's - through Edgmont
Township at the widow Yarrels ~ through Thornburg at Isaac Vernon's **
through West Town at Joseph Hunts and through West Bradford at
Abraham Marshalls and John Newtons.

At the last place we began to set off the fifteen statute
miles and we found it to be about one mile from Philadelphia.

It is believed that either here or at some place about five or
six miles more west there will be found the most level ground.

You can go near one Mr. Thomas Woodward's plantation in
Marlboro Township. He is a surveyor and well acquainted with this
country and can be of great use to you in showing you the
best ground in any part of Chester County contiguous to the County
of Newcastle.

I am sure everybody will be glad to oblige you and
do you all the service in their power as soon as they are made
acquainted with your fullest characters and the business you
are employed in. I heartily wish you a good Journey and am

Gentlemen

Your most humble servant
Richard Peters

To: Messrs: Mason and Dixon
(Editorial note:

On this page is shown the envelope in which the preceding letter was dispatched, viz:)

To

Messrs. Mason and Dixon

Mathematicians

at

Wuaco

1764

January

4 Finished our observations at Philadelphia

Computing the result of the stars true zenith distances from our observations
Computing the result of the stars true zenith distances from our observations
Set out from Philadelphia with a Quadrant to find (nearby) a
place in the Forks of Brandywine having the same Parallel
as the Southernmost point of the City of Philadelphia.

8 Sun. Fixed on the House of Mr. John Harland's (about 31

miles West of Philadelphia) to bring our Instruments to.

9 Returned to Philadelphia

10 Prepared for moving our Instruments

11 The Observatory taken down and put with the rest of our Instruments
into the wagons, except the Telescope, etc., of the Sector

which was carried on the Springs (with Feather bed under it)
of a single Horse chair.

38

1764

January-

12 Left Philadelphia and reached Chester

13 Lodged at Esquire Worths

Arrived at Mr. Harlands and set up the sector in his
Garden (inclosed in a tent), and in the Evening brought the
Instrument into the Meridian, and took the following observations

Star Star

Magnitudes Names

Plane WEST

Right Nearest point

Ascension on the Sector

Revolutions and Difference Apparent
Seconds on the Zenith

Micrometer Distance

17

18

19

20

21

Cloudy

22 Sun.

h

m o

i

R

m

R

II

o

i

Capella 4

59 5

50-

6

46.5

2

38.2

5

47

37.8

4

8 +

Beta Aurigae

4

55+

1

12.5

2

46.0

4

57

30.0

4

6.5

Castor

7

35-

2

15.5

2

11.0

33

5.0

4

26.5

37

Turned the Instrument facing the EAST

Brought the Instrument into the Meridian and took the following Observations

Capella 4

59 5

50-

5

44

2

39.5

5

47

36.5

8

31.5

Beta Aurigae

4

55+

9

4

2

47.7

4

6

8 +

From these Observations finding we were very

near the Parallel

of the Southernmost point of the City of Philadelphia we ordered

Carpenters to Erect the Observatory

Plane EAST Sector in the Tent

Gamma Andromedae

15-

3

14.0

0.0

15

0. ON

3

14.0

Beta Persei

0

5 +

4

0

0

40.0

0

5

3

12

Delta Persei

7

5-

9

14.5

0

30. 5

4

29.5

9

AK

Gamma Andromedae

1

15-

9

11.5

0

5.5

14

54.5

9

17

Beta Persei

0

5+

10

10 +

0

39.6

0

5

39.6

9

23-

Delta Persei

7

5-

7

34.5

0

29

4

31.0

8

11.5

38

Gamma Andromedae

1

15+

5

13-

0

2.2

1

15

2.2

5

10,5

Beta Persei

0

5+

5

45.5

0

39

0

5

39.0

5

6.5

Alpha Persei

9

5-

2

10

1

21

9

3

47.0

3

31

Delta Persei

7

5-

4

1-

0

29.8

7

4

30.2

4

30.5

Gamma Andromedae

1

15+

7

3+

0

1.3

15

1.3

7

2

Beta Persei

0

5+

6

11.5

0

37.5

0

5

37.5

5

26

Alpha Persei

9

5-

5

33

1

18.3

9

3

49.7

6

51+

Delta Persei

7

5-

7

32+

0

29.2

7

4

30.8

8

9.5

Gamma Andromedae

1

15+

3

46.7

0

1.2

15

1.2

3

45.5

Beta Persei

0

5+

3

51

0

38

0

5

38.0

3

13

Delta Persei

7

5-

4

28+

0

29

4

31.0

5

5+

39

1764

January

23 Removed the Sector into the Observatory and in the Evening brought it into the Meridian

Plane WEST

N. B. The Sector stands 9 1/2 yards more South in the Observatory than it did in the Tent,

* therefore 0"3 must be added to all Northern Stars observed in the Tent. 39

Star

Star Right

Nearest point

Revolutions and

Difference

Apparent

Magnitudes Names Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance

h m

o

R

n

R

ii

o

i n

24

Snow

25

Snow

26

Gamma Andromedae

1

15+

6

3+

0

4*7.

1

6

8

Beta Persei

0

5+

5

26

0

41.7

0

5

41.7

6

15.7

Delta Persei

7

5-

6

26

0

27. 2

7

5

50.5

27

Gamma Andromedae

1

15+

11

37+

0

5.7

Hazy

11]

43

Beta Persei

0

5+

10

16.5

0

41.0

0

5

41. 0

H

5.5

Alpha Persei

9

5-

9

50.5

1

11.0

9

3

8

39.5

Capella

5

50-

6

42-

2

29.2

5

47

4

12.5

Alpha Lyrae

1

20+

6

31

2

13.5

1

21

57. 5S

4

17.5

28

Gamma Andromedae

l!

15+

6

48

0

4.5

1

15

7

Qi.5j

Beta Persei

0

5+

6

45;

0

44

0

5

44

7

37

Alpha Persei

9

5-

7i

17.5

1

1CU.5j

9

3;

57.5

6

7?

Delta Persei

Tt

Sr-

6

12

0

27

7

4

5

37

Capella

5

50*

6>

10]

2

293

5

47

3d

39

Beta Aurigae

4

55*

4

8+

3

2.4

4

57

7.

11-

Alpha Lyrae

r

20+

5

20.. 5

2'

13.. 0

1

21

57. OS;

3

7.5

4

29 Sun.,

Gamma Andromedae

11

15;+

2

42., 5

0

5*5

1.

15

5.5N

2:

48

Beta Persei.

fltl

5+

3;

00

0

44.0

0

5

3

44

Alpha Persei

3

5-

6

28

1

12.7

9

3

5

15+

Delta Persei

7

5-

4

50+

0

27. 3

7

4

4

23

Capella,

5

50-

4

30+

2

29.3

5

47

2

1

Beta Aurigae

4

55+

4

9+

3

0*4

4

57

7

10-

m

Cloudy

3;3>

Cloudy

February

1

Cloudy

47

47.8

2

Capella

5

50-

8

23. 5

2

28.2

5

5

47.3

Beta Aurigae

4

55+

8

2

3

2

4

57

11 4

40

1764

Feb.

Star

Star

Right

Nearest point.

Revolutions and

Difference

Apparent

Magnitudes Names

Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance

h m

0

i

R

M

R

ti

0

1 "

3

Delta Persei

7

5-

4

51

0

27.5

7

4

32.5

4

23. 5

Capella

5

50-

6

43. 8

2

31.3

5

47

44.7

4

12.5

Castor

7

35-

10

3+

2

9.4

7

33

6. 6

12

13-

4

Cloudy

5 Sun.

Alpha Cygni

4

30+

14

10-

0

13.0

14

23

Beta Aurigae

4

55+

15

5. 5

3

0.8

4

57

36. 8

18

6+

Castor

7

35-

11

46+

2

11. 2

7

33

4.8

14

5.5

6

Beta Aurigae

4

55+

15

46. 5

3

0.2

4

57

36. 2

18

47-

Castor

7

35-

0

45.5

2

10. 5

7

33

5. 5

3

4

7

Cloudy

8

Beta Aurigae

4

55+

14

1.7

3

3. 8

4

57

39.8

17

5.5

Castor

7

35-

14

39.5

2

9. 2

7

33

6. 8

16

49-

9

Cloudy

10

Alpha Lyrae

1

20+

6

1.5

2

19.8

1

22

3. 8

3

34-

11

Equal Altitudes

of Capella

41

Time by Watch

12

Cloudy

h

m

s

h

m

s

4

12

55

5

29

12 )

4

14

15

5

30

42 f

Hence Capella passed the Meridian of the Transit Instrument

4

15

43

5

32

8 )

at 4h 52m 29s and it was observed to pass the Vertical wire

in the Sector at 4h 52m 11s

13

Alpha Lyrae

1

20+

15

34. 3>

2

17.3

1

22

1.3

13

17

Turned the Instrument

Plane EAST

14

Cloudy

15

Cloudy

16

Cloudy till Alpha Lyrae

1

20+

3

20+

2

24..2

1

22

8. 2

Alpha Lyrae came

5

44.5

17

Cloudy

18

Beta Aurigae

4

55+

6

40.7

2

51.7

4

57

35 k. 7

3

41.0

19 Sun.

Cloudy

20

Capella

5

50-

15

23

2

37

5

47

39.0

18

8

Beta Aurigae

4

55+

m

47

2

50.7

4

57

34. 7

15

48+

Castor

7

35-

14

47

2

8. 7

7

33

7.3

12

38+

Equal Altitudes
of Cape 11a

Time by Watch

-h

m

s

h

m

4

10

16

5

36

4

11

37

5

37

4

12

57

5

38

3 ) Hence Capella crossed the Meridian of the Transit Instrument
20 > aft 4h 54m 29s and it was observed to cross the vertical wire
39) in the Sector at 4h 54m 34s 43

17

41

co

1764

Feb. Star Star

Magnitudes Names

20

Alpha Lyrae

21

Capella

Beta Aurigae

Castor

Alpha Lyrae

22

Capella

Beta Aurigae

Castor

Alpha Lyrae

Right Nearest point

Ascension on the Sector

h m o'

1 20+

5 50-

4 55+

7 35-

1 20 +

5 50-

4 55+

7 35-

20 +

Revolutions and
Seconds on the
Micrometer
R "

7 40.5

10 15

5 22

8 7+

9 48+

6 49+

6 43-

4 33

8 20 -

10 44. 5

6 51-

9 37-

10 27-

7 27. 5

7 7

4 49-

9 14-

11 39.5

Difference

R

2 26. 5

2 37. 3

2 51.0

2 9. 7

2 24. 8

2 38. 0

2 51. 2

2 10. 3

2 25. 8

Apparent
Zenith
Distance
o ' "

1 22

5 47

4 57

7 33

1 22

5 47

4 57 35.2

7 33

1 22

£3 Cloudy

14 CJoudy Mr. Loxley fcarpenter} brought level*, etc. N for measuring thy 35 Statute nules Horizontal.
2a Cloudy

2GSufi. Cloudy til] Alpha Lyrae come 1

27 Cloudy

Castor 7

Alpha Lyrae 1

20+

12

35-

9,5

2

26. E)

1

35-

15

13

48-

38+

2

9.4

7

33

6.6

20+

9

11

14

39. 5

2

25. 5

1

22

9. 5

44

42

1764

January-

Star Zenith Distances at the point N
Sector in the Tent. Plane EAST

Star

Star

Star

Star

Name

Name

Name

Name

Gamma Andromedae

Beta Persei

Alpha

Persei

Delta Persei

o

i

m

o

t

ft

o 1

ti

o

«

it

1

15

00.0

0

5

40.0

7

4

29.5

0

5

39.6

7

4

31.0

1

15

02.2

0

5

39. 0

9 3

47.0

7

4

30.2

1

15

01.3

0

5

37.5

9 3

49.7

7

4

30. 8

1

15

01.2

0

5

38.0

7

4

31.0

Mean, January 20

1

15

1.2

0

5

38.8

9

3

48.3

7

4

30.5

Aberration in Declination

-10.0

- 9. 1

-11.4

-10.4

Deviation in Declination

- 3.3

- 5.7

- 6. 2

- 6.7

Precession from 1 January 1764

-1.0

- 0.8

- 0.7

- 0.7

Refraction

+ 1.4

+ 0. 1

+10. 5

+ 8.3

Observatory South of the Tent

+ 0.3

+ 0.3

+ 0.3

+ 0.3

Mean Zenith Distances, 1 Jan. 1764

1

14

48.6

0

5

23.6

9

3

40.8

7

4

21.3

Sector in the Observatory

Plane WEST

Gamma Andromedae

Beta Persei

Alpha Persei

Delta Persei

January

o

i

it

o

i

M

o

i

it

o

r

ti

26

1

15

4.7

0

5

41.7

7

4

32.8

27

1

15

5.7

0

5

41.0

9

3

57. 0

28

1

15

4. 5

0

5

44.0

9

3

57. 5

7

4

33.0

29

1

15

5.5

0

5

44. 0

9

3

55.3

7

4

32.7

Mean January 27. 5

1

15

5. 1

0

5

42.7

9

3

56.6

7

4

32.8

Aberration in Declination

-9.0

- 8.6

-11.1

-10. 3

Deviation in Declination

-3. 3

- 5.7

- 6.2

- 6.7

Precession from 1 January 1764

-1.3

- 1. 1

-1.0

- 0.9

Refraction

+ 1.4

+ 0.1

+ 10.5

+ 8.3

Mean Zenith Distance, 1 Jan. 1764

1

14

52.9

0

5

27.4

9

3

48. 8

7

4

23. 2

Mean Z. D., 1 Jan. 1764, Plane EAST

1

14

48.6

0

5

23.6

9

3

40.8

7

4

21.3

True Z. D. at Mr. Harlands, 1 Jan. 1764

1

14

50. 8

0

5

25. 5

9

3

44. 8

-7

4

22. 2

True Z. D. at Philadelphia

1

14

39. 5

0

5

14.45

9

3

32. 1

7

4

11. 7

Hence we are South of the Parallel required

0

0

11.3

0

0

11. 0

0

0

12. 7

0

0

10.5 45

Star Zenith Distances at the point N
Zenith Distances, Plane WEST

1764

Cape 11a
o 1

11

Beta Aurigae
o ' "

Castor
o »

it

Alpha Lyrae
o ' "

January

27

5

47

46. 8

27 1

21

57. 5

28

5

47

47, 0

28

4

57

38.4

28 1

21

57.0

29

5

47

46. 7

29

4

57

36.4

1

21

57.3

February

2

5

47

47. 8

2

4

57

38.0

Aber.

-9.5

3

5

47

44. 7

3

7

33

6.6

Devi.

-9.4

5

4

57

co

co’

CO

5

7

33

4. 8

Prec.

+0. 2

6

4

57

36.2

- 6

7

33

5. 5

Refr.

+ 1. 5

8

7

33

6. 8

1

21

40. 1

11 1

22

3. 8

13 1

22

1.3

Mean

Aberration in Declination

30

5

47

46.6

-7.4

1

4

57

37. 2
-5. 7

5.5

7

33

5.9

-0.6

12 1

22

2. 5
-13.0

Deviation

-8.8

-9. 2

+9. 1

-9.4

Precession from 1 Jan. 1764

-0.4

-0. 1

-0. 7

+0.3

Refraction

+6. 7

_

+5. 8

+ 8.8

+ 1. 5

Mean Z. D. 1 January 1764

5~~

47

36. 7

57

28. 0

~

33

22. 5

~

21

41.9

1 21 40. 1

1 21 41.0

43

Plane EAST

1764

February

Mean

Aberration

Deviation

Precession from 1 Jan. 1764
Refraction

Mean Z. D. 1 Jan. 1764
The Same, Plane WEST
True Z.D. at Mr. Harlands,
The Same at Phila.

Hence we are South of the

Capella Beta Aurigae

i _ i it

o' o'

18

4

57

35.7

20

5

47

39.0

20

4

57

34.7

21

5

47

38.7

21

4

57

35. 0

22

5

47

38.0

22

4

57

35.2

21

5

47

38.6

21

4

57

35. 2

-8.0

-6.9

-8.8

-9.2

-0.7

-0.2

+6.7

+5.8

T

47

27.8

4~

57

24.7

5

47

36.7

4

57

28.0

1 Jan.

5

47

32.3

4

57

26.3

5

47

21.6

4

57

14. 15

0

10.7

0

12. 1

Castor Alpha Lyrae

o

t

o

i

m

16

1

22

8.2

20

7

33

7.3

20

1

22

10.5

21

7

33

6.3

21

1

22

8. 8

22

7

33

5.7

22

1

22

9.8

26

1

22

10.8

21

7

33

6.4

21

1

22

9.6

+0.5

-14.8

+9. 1

-9.4

-0.95

+0.35

+8.8

+ 1.5

T

33

23.8

T

21

47.3

7

33

22.5

i

21

41.0

7

33

23. 1

l

21

44.2

7

33

31.75

l

21

53.2

8.6

0

9.0

required Parallel

From the foregoing the mean of the results from the different stars as follows.

, n

Gamma Andromedae

Beta Persei

Alpha Persei
Delta Persei

Capella

Beta Aurigae

Castor

Alpha Lyrae

Mean

o ioT= ;3J56;8 yards (UWM> .miles Uo;a degree) that the Sector is South of the

iFgsalie V of the SSnutlasnmnnstjjsaintectftthe'.City of Philadelphia
US. B. 4fter measuring tthe Lt6 Statute ,miles(Horizontal and finding the arch in the
>Beaven6,corneapontiiug, iif it;dQes not;agree to 69. 5 miles to a degree we
should account tfthe sasumrdingly.

46

44

For the Latitude of the Observatory at Mr. Harlands

Delta Persei

Capella

Beta Aurigae

Castor

Alpha Lyrae

o

i

m

0

1 »■

0

it

0

t

it

0

t

11

True Z. D., 1st Jan. 1764 7

4

22:2

5

47 32.3

4

57

26.3

7

33

23. 1

1

21

44.2

Stars Declinations by Dr. Bradley 47

0

40.0

45

43 53.0

44

53

44.2

32

22

56.8

38

34

34.0

Latitude by the different stars 39

56

17.8

39

56 20.7

39

56

17.9

39

56

19.9

39

56

18. 2

20.7

17.9

19.9

_ 18.2

Mean 39 56 18. 9 = The Latitude of the Observatory in Brandywine

39 56 29. 1 = Latitude of the South point of the City of Philadelphia

Difference 10.2 That we are to the Southward at Mr. Harlands, but

The mean of the results from the Zenith distances of 8 stars
must be preferred to that of five.

1764

February 28 Finished our observations of the stars Zenith Distances at Mr. Harlands

in the Forks of Brandywine.

29 Computing the true Zenith Distances of the stars from our observations.

March 1 Computing as on February 29

2 Cloudy

« Cloudy

Cloudy (Sunday)

By the Pole Star's transiting the Meridian we placed a mark in the Meridian northward,
but it was rendered a little dubious on account of flying clouds.

6 Cloudy

7 Cloudy

8 Cloudy

9 Cloudy and Snow

10 Cloudy

11 Cloudy (Sunday)

12 Cloudy and Snow

13 Cloudy and Rain

14 Cloudy

15 Cloudy_

16 Proved the mark in the Meridian Northward

17 Employed one man, cutting a visto in the Meridian Southward. This
Evening at 8h 21m 59s apparent time the Eclipse of the Moon Ended.

18 (Sunday) N. B. The edge of the Sun's Shadow on the Moons disk was the best defined I ever saw,
the air was so clear it was remarkably distinct from the penumbral shade.

19 Employed four men cutting a visto in the Meridian Southward

20 Employed four men as on March 19.

21 Employed four men cutting a visto in the Meridian Southward

22 Employed four men cutting the Meridian Southward as before

23 Employed four men as on March 22

24 Employed four men as on March 22

25 (Sunday)

26 Employed five men as on March 22

27 Employed five men as on March 22

28 Employed five men as on March 22

29 Employed five men as on March 22

30 Employed five men as on March 22

31 Employed five men as on March 22

April 1 (Sunday)

45

1764

April

April

2 Began to measure from our observatory (at Mr. Harland's). Employed the five men.

Chains

Links

Levels

9

61

4

These 4 levels 22 feet each (The Levels were found not so

proper for use as the 16. 5 feet)

2

91

Entered the Brandywine

28

00

Entered the Brandywine again

9

00

of the 16. 5 feet Levels, which we shall use through the whole

9

00

7

00

To a stob on the N. side of the Brandywine the third time.

2

04

40

To a mark on the S. side of the Brandywine

60

59

89

141

To a mark in Mr. Wilson’s field

35

25

14 =

Sum

Rain

30

00

Measured the chain

4

00

31

9

00

10

30

46

00

10

40

00

This reached to the Road leading from Peckway to Wilmington
wanting half a chain.

54

00

8

49

80

70

00

20

6

00

8

26

00

10

5

00

5

4

00

11

16

00

o

5

00

o

30

26

00

6

This reaches to the North Edge of the high road leading from

382

~80~

191

Philadelphia to Nottingham. Mr. Charles Hall’s, East about

47

75

seventy yards.

430

55 =

Sum

1764

April

Chains

Links

Levels

46

00

10

Found the chain a little too long. Corrected it.

10

00

30

3

00

7

7

50

18

44

50

10

00

10

5

00

20

28

38

9

55

To a tree marked with 5 notches (in a wood) about 150 or 200
yards South East of Mr. Milhouses, Proved the Meridian and
found it very exact.

160

93

105

187. 18 = Sum

Employed five men in continuing the Meridian
Employed five men as on April 6th

9

80

00

This reached to Mr. Joseph Freads. Chain correct.

31

00

20

00

10

00

29

10

03

161

03

~5ST

175. 78 = Sum

10

Employed

five men

continuing the Meridian

11

Employed five men as on

April 10th.

12

80

00

9

This morning examined the chain and found it just.

Employed five men measuring, etc.

24

00

8

7

5

6

2

50

35

00

47

00

30

This just crosses Pikes creek

11

14

60

92

To a tree in the fence of the South end of a ground belonging
to Mr. Bryan.

273

"06"

Too"

298. 06 = Sum

51

Miles Chains Links
Sum 14 66 70

16 23 = 101*5 = 357 yards. The Observatory South of the Parallel of the

Southernmost point of the City of Philadelphia
"l5 2 93 Set the Observatory back 2 1/2 chains

13 Returned to Brandywine with the Labourers.

14 Prepared for removing, employed the five men as before.

15 (Sunday)

16 Ditto.

17 Ditto.

47

1764

April

18

19

20
21
22

23

24

25

26

27

28

29

30
May

1

2

3

4

6

8

10

11

12

Set out from Brandywine with our Observatory and Instruments in four waggons. Employed the five
Labourers in carrying one of the Instruments.

Employed five men setting up the Observatory. (Rain the greatest part of the day.)

Ditto.

Four Labourers returned home and were discharged, one kept to provide provisions, etc. Set up the Sector,
(Sunday) Set out to Philadelphia to acquaint the Commissioners we were arrived at the south end
of the 15 miles.

At Philadelphia.

At Philadelphia. (Sent an Express to Horatio Sharp, Esquire, Governour of Maryland, to acquaint him of
our being at the South end of the 15 miles.)

Returned from Philadelphia.

Cloudy

Cloudy and rain.

Ditto. Heavy Rain.

(Sunday) Ditto.

Cloudy

Cloudy

Cloudy

Brought the Instrument into the Meridian. 53

Star

Star

Right

Nearest Point

Revolutions and

Difference

Apparent

Magnitudes

Names

Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance

h m

R

it

R

it

0

i

M

Cloudy

Castor

7

20+

6

29

7

20

15.3

6

44+

very faint

Alpha Lyrae

10-

6

46+

0

47.3

1

9

12. 7

5

51

Alpha Cygni

4

45-

6

47

2

19.0

4

42

57.0

9

14

faint

(Sunday)

Castor (I now opened

7

20+

7

48. 5

0

13.2

7

20

13.2

the aperture)

8

10-

still faint

Alpha Lyrae

1

10-

7

22

0

49.5

1

9

10. 5

6

24. 5

Capella

6

0+

6

16+

0

29.8

6

0

29. 8

5

38. 5

Alpha Lyrae

1

10-

8

42. 5

0

50.0

1

9

7

44. 5

Capella

6

0+

5

43

0

28+

6

0

28.3

5

15-

Capella

6

0+

3

50

0

29.0

6

0

3

21

Alpha Lyrae

10-

8

24. 5

0

49. 5

9

7

27

Alpha Lyrae

10-

8

16+

0

48.8

9

7

19. 5

Alpha Cygni

4

45-

9

45. 5

2

15.2

4

43

0.8

12

9-

54

Alpha Lyrae

10-

6

34

0

51.0

9

9.0

5

35

Alpha Cygni

4

45-

8

6-

2

17.8

4

42

10

23. 5

Alpha Lyrae

10-

6

28

0

50

1

9

5

30

Alpha Cygni

4

45-

7

9

2

13.3

4

43

2.7

9

22+

!

111.3’*

SZ

48

1764

May

13

14

15

Star

Star

Right

Nearest Point

Revolutions and

Difference

Apparent

Magnitudes

Names

Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance

h m

o

i

R

it

R

ii

o

i it

(Sunday)

Cape 11a

6

0+

10

32

0

30.0

6

0 3<

10

02

Castor

7

20+

10

51

11

11

Alpha Lyrae

1

10-

11

46+

0

52.3

1

9 7.

10

46

Delta Cygni

4

50+

14

41+

0

6.3

4

50 6.

14

35

Gamma Cygni

0

15-

11

6.5

2

16.5

0

12 59.

8

42

Alpha Cygni

4

45-

8

26. 5

2

16.0

4

43

10

42. 5

Began to measure back again to Mr. Harlands where the Observatory last stood in the Forks of
Brandywine. Employed five men.

Chains

Links

Levels

72

00

31

47

10

36

24

18

10

80

00

25

70

279

20

75

18

75

297

95 =

Sum

10

00

29

19

00

20

20

00

10

30

00

13

78

80

157

80

18

00

175

80 =

Sum

40

00

13

4

50

15

6

00

10

47

00

8

00

10

00

10

10

00

47

72

169

22

74

18

50

187

72 =

Sum

To a ma^k in a wood.

From the last Mark to a Mark near Mr. Milhouse’s.

From the last mark to a mark to the North Side of the
Road leading from Philadelphia to Nottingham.

55

49

1764

May

15

16

17

Chains

Links

Levels

30

00

20

10

00

12

00

10

38

00

80

00

80

00

71

50

5

47

00

6

1

00

15

39

80

409

30

56 From the last mark to one in Mr. Wilson's field.

14

00

423

30 =

Sum

21

5

03

59

2

04

8

00

15

10

00

14

7

00

2

00

26

50

7

38

109 From the mark in Mr. Wilson's field to where the Sector stood,

95

20 =

Sum

Upon casting up these measurements I found there was a disagreement between the
mark in Mr. Wilson's field and that by the Road leading from Philadelphia to Nottingham;
and also between that in the Road and Mr. Milhouse's, we therefore began again at the

Mark in Mr. Wilson's field and measured in our return as follows.

34

00

39

1

40

38

10

40

00

80

00

30

80

33

3

4

00

11

10

00

13

00

25

27

61

128 From the mark in Mr. Wilson's field to the Road from Philadelphia

to Nottingham.

56

57

50

From the Road to the mark near Mr. Milhouse's.

1764

May

Chains

Links

Levels

18

60

00

24

3

00

7

50

18

44

50

10

00

10

00

20

37

94

164 94 99

22 _25_

187 19 = Sum

From the Observatory to the mark
in Mr. Wilson's field

From Mr. Wilson's field to the Road
from Philadelphia to Nottingham

From the above Road to the
Mark near Mr. Milhouse's

From Mr. Milhouse's to
the mark in---

From the last mark to the
mark in Mr. Bryans field

For small inclinations of Hills, etc.,

71 Links ought to be subtracted from the Sum and it leaves
The Parallel of the South Point of Philadelphia North of the
Sector in the Forks of the Brandywine
Sum = 14 miles 74 chains 92 links

Miles Chains

15 00

14 74

Chains

Links

Chains

Links

95

14

=

First Measure

95

20

=

Second Measure

Mean =

95

17

430

55

-

First Measure

423

30

=

Second Measure

Mean =

423

25

423

19

=

Third Measure

187

18

-

First Measure

The mean of

187

72

Second Measure

the first

187

18

187

19

=

Third Measure

and third

175

78

=

First Measure

175

80

=

Second Measure

Mean =

175

79

298

06

=

First Measure

297

95

=

Second Measure

Mean =

298

01

Sum =

1179

40

t accounted for (not measured with the

! levels) we Judge

Chains

Links

1178

16

69

23

1194

Links

00

92

92

58

Hence the Mark in Mr. Bryan's field is
the Sector was set North from the above mark
The Sector now stands

15 Statute miles South of the Parallel required.

08

52

North of true point and as

60 North of the point (and)

The Distance from the Observatory in Brandywine to the mark in Mr. Bryan's field
Distance of the Observatory in Mr. Bryan’s field North of the mark *
rest the Horizontal distance between the Points where the Sector stood

Chains Links

1178 69

2 52 Subtract

1176 17

51

1764

May-

19 Attended the Commissioners of both Provinces at Newcastle.

Star

Star

Right

Nearest Point

Revolutions and

Difference

Apparent

Magnitudes

Names

Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance

h m

o

i

R

it

R

m

o

i

it

Alpha Lyrae

1

10-

17

25

0

54.5

1

9

5.5

16

22. 5

Delta Cygni

4

50+

16

30.5

0

8.0

4

50

16

22. 5

Gamma Cygni

0

15-

18

30

2

16.0

0

13

16

14

Alpha Cygni

4

45-

13

22

2

15.0

4

43

1.0

15

37

20

(Sunday)

Delta Cygni

4

50+

4

50

0

9.0

4

50

4

41

Gamma Cygni

0

15-

9

0. 5

2

18.0

0

12

58.0

6

34. 5

Alpha Cygni

4

45-

5

34

2

14.5

0

43

1.5

7

48. 5

21

Attended the Commissioners.

22

Attended the Commissioners.

3.81

23

Alpha Lyrae

1

10-

8

7-

1

4.2

1

9

7

2.5

Delta Cygni

4

50+

8

5+

0

11.3

4

50

7

46

Gamma Cygni

0

15-

7

38

2

19.0

0

5

19

Alpha Cygni

4

45-

5

38. 5

4

43

0.5

8

2

24

Cloudy

4.3

9

25

Alpha Lyrae

1

10-

9

29+

1

1

3. 7

8

25

Delta Cygni

4

50+

8

32+

0

9.6

4

50

9.6

8

23-

Gamma Cygni

0

15-

8

41.5

2

20.0

0

12

6

21.5

Alpha Cygni

4

45-

6

1+

4

43

2.3

8

15

Turned the Instrument and made the following observations

Plane WEST

Gamma Cygni

0

15-

2

15+

2

23.4

0

12

52.6

4

39-

Alpha Cygni

4

45-

3

49-

4

43

4.3

1

37

27

(Sunday)

Alpha Lyrae

1

10-

4

5

1

9.0

1

8

59. 0

5

14

Delta Cygni

4

50+

5

35.5

0

14. 2

4

50

14.8

5

50+

Gamma Cygni

0

15-

7

28

2

25.0

0

12

51.0

10

01

Alpha Cygni

4

45-

6

44. 5

2

11.8

4

43

4. 2

4

33-

52

1764

May Star

Magnitudes

28

29 Cloudy

30 Cloudy

31 Cloudy
June

1

2 Cloudy

3 (Sunday)

4

6

7

Star

Names

Capella
Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni

Capella

Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Capella
Delta Cygni
Gamma Cygni
Alpha Cygni
Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Alpha Lyrae
Gamma Cygni
Alpha Cygni

Right

Ascension

h m

Nearest Point Revolutions and
on the Sector Seconds on the
Micrometer

o

i

R

u

6

0+

5

43+

6

24

1

i

o

T—4

5

1.5

6

10

4

50+

6

2

6

17

0

15-

6

7.5

8

32.5

4

15-

8

14

6

2

6

0+

5

40-

6

20

1

10-

5

11. 5

6

21.5

4

50+

6

38

7

01

0

15-

7

30.5

10

3.5

4

45-

9

32.5

7

24

1

10-

7

28+

8

36. 5

4

50+

10

9

10

24+

0

15-

9

39+

12

13

4

45-

12

12+

10

2-

6

0+

9

10.8

9

42.5

4

50+

9

29-

9

45.5

0

15-

10

32. 5

12

50-

4

45-

12

35. 5

10

26

1

10-

7

50. 5

9

8+

4

50+

10

42-

11

6

0

15-

10

32.5

13*

6. 5

4

45-

15

13-

19

4.5

1

10-

4

47+

6

6

0

15-

6

17-

8

44-

4

45-

7

38

5

30

Difference

Apparent

Zenith

Distance

R

it

o

»

tt

0

32.7

6

0

32.7

1

8.5

1

8

59.5

0

15.0

4

50

15.0

2

25.0

0

12

51.0

2

12.0

4 43
hazy

4.0

0

32.3

6

0

32.3

1

10.0

1

8

58.0

0

15.0

4

50

15.0

0

12

51.0

2

8.5

4

43

7.5

1

8.2

1

8

59. 8

0

15.3

4

50

15.3

2

25.7

0

12

50.3

2

10.6

4

43

0

31.7

6

0

0

16. 8

4

50

16.8

2

26.3

0

12

49.7

2

9.5

4

43

6.5

1

9.8

1

8

58.2

0

16.3

4

50

16.3

2

26.0

0

12

50.0

2

8.2

4

43

7.8

1

10.7

1

8

57.3

2

27.0

0

12

49.0

2

8.0

4

43

8.0

53

1764

June Star

Star

Right

Nearest Point

Revolutions and

Difference

Apparent

Magnitudes

Names

Ascension

on the Sector

Seconds on the

Zenith

Micrometer

Distance

h m

o

i

R

n

R

ii

0

i

ii

8

Alpha Lyrae

1

10-

5

11

1

10.7

1

8

57.3

6

22-

Delta Cygni

4

50

5

25

0

18.0

4

50

18.0

5

43

Gamma Cygni

0

15-

5

17.5

0

12

48.0

7

45.5

Alpha Cygni

4

45-

7

45-

4

43

8.3

5

37

9

Alpha Lyrae

1

10-

5

3

very hazy

6 19.5

10 (Sunday)

11 Computing the true Zenith Distances of the Stars.

12 Ditto. The results whereof follow. 63

Cape 11a

1764

o

i

II

May

7

6

0

29.8

8

6

0

28.3

9

6

0

29.0

13

6

o.

30.0

Mean of first set

10

6

0

29.3

Aberration

-1.5

Nutation

-9.0

Precession from 1 Jan.

1764

-1.9

Refraction

+7.0

True Zenith Distance 1 Jan. 1764

6“

0

23.9

54

Zenith Distance of Stars near the end of the 15 miles South of Philadelphia

Plane EAST

May

Alpha Lyrae
o » "

May

Delta Cygni
o ' "

May

Gamma Cygni
o * "

May

Alpha Cygni
o ' "

6

1

9

10.5

13

4

50

6.5

13

0

12

59.5

10

4

43

0. 8

7

9

10.0

Abb.

-15.0

11

4

42

58. 2

9

10.5

Devi.

-8. 1

12

4

43

2.7

11

9.0

Prec.

+4.0

13

4

43

0.0

12

10.0

Ref.

+0.2

13

7.7

0

12

40.6

11.5 (Mean date)

Mean of the 1st Set 10

1

9

9.6

19

*

4 O

* A

4

43

0.4

Aberration

-12.3

20

Abb.

+16.5

Nutation

-9.4

23

Devi.

+7.6

Precession from 1 Jan. 1764

+ 1. 1

25

Prec.

-4.5

Refraction

+1.2

22

Ref.

+5.5

True Z. D. 1 Jan. 1764

1

8

50.2

Abb.

Mean

4

43

25.5

19

4

43

1.0

20

43

1. 5

23

43

0.5

25

43

2.3

22

4

43

1.3

True Z. D. the 1st

Abb.

+ 14.9

of Jan. 1764 from the mean

4

50

33. 15

0

12

40.6

Nutation

+7.6

of all the five Observations

Prec.

-4.8

Ref.

+5.5

19

1

9

5.5

Mean

4

43

24.5

23

9

3.8

Mean

4

43

25.4

25

9

3.7

Mean of the 2nd Set 22

1

9

4.3

True Zenith Distance

Aberration

-9.5

1st of Jan. 1764 from 4

Nutation

-9.4

the mean of all the Observations.

Precession

+ 1. 1

Refraction

+ 1.2

Mean

1

8

47.7

Mean above

8

50.2

Mean of all the observations
the 1st Jan. 1764

1

8

49.0

65

55

Zenith Distance of Stars at the end of 15 miles South of Philadelphia

Plane WEST

Capella

Alpha

Lyrae

1764

o

i

ii

o

f

n

May

27

1

8

59.0

28

6

0

32.7

8

59.5

June

1

0

32.3

8

58.0

8

59.8

0

31.7

8

58.2

8

57.3

8

8

57.3

Mean 1 &

3

6

0

32. 2 June 1

1

8

58.4 June 3

Aberration

+ 1.4

-6.3

Nutation

-9.0

-9.4

Precession from 1st Jan. 1764

-2.2

+ 1. 1

Refraction

+7.0

+1.2

Mean Zenith Distance 1st Jan. 1764, Plane WEST

6

0

29.4

1

8

45.0

Ditto., Plane EAST

6

0

23.9

1

8

49.0

True Zenith Distance, the 1st of January 1764 at

6

0

26.6

1

8

47.0

the Sector.

The Sector stands North of the true point

+5.20

-5.20

7 Chains, 91 Links (51*20)

True Zenith Distances 15 Miles South of the

Southernmost point of the City of Philadelphia

6

0

3L 80

1

B

41. B0

on the 1st of January 1764

And these (and those on

the following page)

> are

our Radical Points for running the Western Line.

Zen ith Distances of Stars at the End

of 15 miles South of

Philadelphia

Plane WEST

Delta Cygni

Gamma Cygni

Alpha Cygni

1764

o

1

"

o

i

ii

o

i

n

May

26

0

12

52. 6

4

43

4. 3

27

4

50

14.8

12

51.0

43

4.2

28

4

50

15.0

12

51.0

43

4.0

June

3

50

15.0

12

51.0

43

7. 5

4

50

15.3

12

50.3

43

5.4

5

50

16. 8

12

49. 8

43

6.5

a

50

16.3

12

50.0

43

7.8

12

49.0

43

8.0

a

50

18.0

12

48.0

43

8.3

Mean

3

4

50

15.9

0

12

50.3

4

43

6.2

Aberration

+ 10.4

-11.3

+ 12. 8

Nutation

+8. 74

-8. 1

+7.6

Precession from 1st Jan. 1764

-3.40

+4.6

-5.2

Refraction

+5. 6

+ 0.2

+5.5

Mean Zenith Distance, 1st Jan. 1764

4

50

37.24

0

12

35.7

4

43

26.9

Plane of the Sector (WEST)

Ditto, Plane EAST

4

50

33. 15

0

12

40.60

4

43

25. 0

True Zenith Distance, the 1st of Jan. 1764

4

50

35. 19

0

12

38.20

4

43

25.95

at the Sector

The Sector stands North of the true point

+5.20

-5.20

+5.20

7 Chains 91 Links = 5"20

True Zenith Distances 15 miles South of the

Southernmost point of the City of Philadelphia 0 12 33.00 4 43 31.20

on the 1st of January 1764

And these (and those of the preceding page) are Radical
Points for running the Western Line.

66

67

56

From the foregoing observations the Zenith

6°

0

Distance of Capella at the Observatory

A

In the Forks of Brandywine their

5°

47

Zenith Distances were

12

Difference

0°

n

26. 6 N, and of Alpha Lyrae

i°

08*

47"0S

32^3 N, and Alpha Lyrae

i°

21*

44"2 N

n

54.3

0°

f

12

II

57,2

57.2

Mean 0° 12 1 55l r fT This corresponds to 1176 chains 17 links =

The distance on a Horizontal measure between the points where the Sector stood. Hence then the Real quantity
corresponding to the 10.'5 that the Sector stood South in the Forks of Brandywine, we have thus

As (12 1 55l'8) : (1176 chains 17 links) : : 10. 5 : (15 chains 92 links)

But in our measurement we allowed 16 chains 23 links for lol's. Hence the true point is 0 chains 31 links South of
the point 7 chains 60 links that is 7 chains 91 links South of the Sector in the Observatory. And the angle correspond¬
ing to this will be as

(1176. 17 chains) : (12' 55l ? 8) : : (7 chains 91 links) : $'.'2 to be applied to the Star Zenith Distances, all ready

done in the page before.

As (12* 55^8) : (1176 chains 17 links) : : 60' : (5457 chains 86.5 links) = 68. 223 miles

Hence 33. 35 yards = one second, therefore 100. 05 feet = l”. This determination by two stars observed at

Brandywine and at the end 15 miles South: The following by three stars at thesaid end and at Philadelphia.-

NOTE: The Point 15 miles South of the Southernmost Point of the City of Philadelphia is situated in Mill
Creek Hundred in the County of Newcastle, in a Plantation belonging to Mr. Alexander Bryan. The Middle of
the Front of Mr. Bryan’s House, bears from the point 37° 52' Northwesterly distant 23. 38 chains (each chain
22 yards). It is close by the East side of a small Run, the Head of which is due North distant 5. 00 chains.
From the Point to the Middle of a small rivulet called Muddy Run, on a due South course is 7. 15 chains.

For the Latitude at the End of

Capella

n l

n

True Zenith Distance 1st January 1764

6

0

31. 8

Declination, 1st Jan. 1764

45

43

53.0

Latitude

39

43

21.2

15.8

17.7

Mean

IF

43

18.2

The Latitude of South Point of Phila.

39

56

29. 1

Difference

0

13

10.9

15 Miles South of Philadelphia

Alpha Lyrae Alpha Cygni

n 1 ” o’"

1

08

41.8

4

43

31.2

38

36

34.0

44

26

48.9

39

43

15.8

39

43

17. 7

= Latitude North

Corresponding to 15 Horizontal Statute Miles. Then

as (13 1 lol*9) : 15 : : 60* ; 68.277

B. Mr. Bryan's

P. The point 15 miles South of Philadelphia
S. A Station North of the point P, and B due
West from S.

As P S 1846 3. 2662317

Rad 10.

S B 1435 3. 1568519

Tang Angle P (37° 52*) 9. 8906202 ,

That is, Mr. Bryan's House bears 37° 52 Northwesterly

As sin B (52° 08') 9. 8973199

P S 1846 3.2662317

Rad 10.

P B 23.38 3.3689118 Figure

Hence the distance of Mr. Bryan's House from the Point is 23. 38 chains. 69

\e>o.o(

57

Memoranda

Our Parallel = that of the South point of Philadelphia
in the Forks of Brandywine; fell about
16 chains North of what the Surveyor made it (about
28 years since) when they ran the Temporary Line:

But it agreed very near to what one Mr. Taylor
made it some years before.

Our Point 15 miles South of Philadelphia came out 46
chains North of what it was settled when the Temporary
Line was run: But at this time it was agreed between
the Proprietors that it should be 15. 25 miles and some
odd chains South of the Southernmost point of the City
of Philadelphia.

The Parallel from Philadelphia (South Point) was run by
former Surveyors three times by Compass; by which it appears
the point from whence we began to run our 15 miles South
is 31 miles chains West from Philadelphia.

1764

June

13 Packing up the Instruments and preparing to set out for the Middle Point (of the Peninsula
formed by the Sea and Chesapeake Bay) in order to run the Tangent Line.

14 Waggons etc. arrived at Newcastle with Tents, etc.

15 Sent our Instruments from the Observatory to Capt. Rice's.

16 Engaged our old hands at Brandywine (Except Mr. Baily) to go with us.

17 (Sunday)

18 The Waggons set out from Newcastle.

19 Joined the waggons and arrived at Dover at night.

20 At Esquire White's.

21 At Mr. Brown's.

22 At the River Nanticoke; pitched our Tents on its Banks.

23 Engaged ax men, etc. The whole company including Steward, Tent keepers, Cooks, Chain
carriers, etc. amounting to 39. Two Waggons, Eight Horses, etc.

24 (Sunday)

25 Crossed the River Nanticoke in canoes and went to the Middle Point, fixed up the
Transit Instrument and began to produce an arch of a Great Circle in the direction last run.

26 Produced the Line and set up the 1st, 2nd and 3rd Mile Posts,

27 Rain

28 Produced the Line and set up the 4th and 5th Mile Posts

29 Fixed the 6th Mile Post

30 Produced the Line across the River Nanticoke. Measured the breadth of the River by angles
taken by a Hadley's Quadrant and a Base Line upon the North Side of the River as by the Figure,

Entrance of the River from the Middle Point is 6 Miles 70 Chains 25 Links
(Sunday)

Put down the 7 Mile Post

Put down the 8th and 9th Mile Posts

Put down the 10th and 11th Mile Posts

Put down the 12th, 13th and 14th Mile Posts

Put down the 15th Mile Post

Put down the 16th Mile Post

(Sunday)

Figure

58

1764

July

3

July

9

10

11

12

13

14

15

16

17

18

19

20
21
09

24

25

26

27

28

29

30

31

August

1

2

3

4

5

6

7

8
9

10
11
12

13

14

15

16

17

18

19

20
21

For the breadth of the River Nanticoke

(Editor's transcription

log 8 = 0. 9030899

log sin 46° 02' = 9, 8571799

10.7602678
log sin 390 35' = 9.8042757

log NS = 0.9559921

N S = 9 chains 4 links)

(Original Documentation)
as sine 39 ° 35' 9.8042757

to 8 ch. , 0.9030899

: : Sine 46® 2 1 9. 8571779

to N S 9 chs 4 links 0. 9559921

Produced the line and set the 17th, 18th and 19th Mile Posts

Produced the Line and set the 20th Mile Post

Put down the 21st Mile Post on the South Side of Marshy Hope

Set the 22nd

Set the 23 and 24th

Gave the overseer of the Ax Men a proper direction, and set out for
Coll. Loyds in Talbot County, Maryland, about 40 miles distant.

(Sunday)

Produced the Line and Set the 25th and 26th Mile Posts

Ditto 27th and 28Ui

Ditto 29 and 30th

Ditto 31 and 32

Ditto 33 rd

Ditto 34, 35, and 36th
(Sunday)

Ditto 37

Ditto 38 and 39th

Ditto 40 and 41st. Crossed the River Choptank
Ditto 42 and 43rd.

Produced the Line

Ditto and fixed the 44th Mile Post

(Sunday)

Ditto and fixed the 45th and 46th
Ditto. 47th and 48th

Ditto. 49th and 50th
Ditto. 51st
Ditto. 52.and 53
Ditto. 54 and 55
(Sunday)

Ditto. 56th Mile Post
Ditto. 57 and 58th
Ditto. 59th and 60th
Ditto. 61
Ditto. 62

Ditto. 63 and 64th
(Sunday)

Ditto. 65 and 66th
Ditto. 67th

Produced the Line and fixed the 68th and 69th Mile Posts. The 69th Mile Post Stands on
the South Side of Bohemia River near low water mark.

Produced the Line and put down the 70th Mile Post.

Ditto. 71 . _

Ditto. 72 and 73rd. Sent two Expresses viz., one to his Excellency Horatio Sharp, Esquire,
Governor of Maryland, and the other to the Honourable James Hamilton, Esquire, at Philadelphia
to acquaint them that we expected to be up with the Line in 8 or 10 days.

(Sunday)

Set the 74th Mile Post

Ditto. 75th and 76th. Crossed Broad Creek

Figure

73

74

75

59

1764

August

22 Ditto. 77th

23 Ditto. 78 and 79th

24 Ditto. 80th

25 Ditto. 81st and produced the Line till we judged we were past the Point settled before to be

the Tangent Point in the circle round Newcastle of 12 Miles Radius.

26 (Sunday) In the Evening sent the Waggon to Philadelphia to be repaired, and to
bring four small Tents, etc.

27 Opened a Visto and produced the Line run (by the former surveyors) from Newcastle
Court House 'till it intercepted the Line we Run.

The Distance from the Point of Intersection above mentioned, and
the Point esteemed to be the Tangent Point in the Circle round
Newcastle of 12 Miles Radius is = 22. 51 Chains. *

The Distance from the Point marked Middle to the Said Point of
intersection is = 81 Miles 78 Chains 31 Links. (The

distance will be 81. 78. 25 when at Right angles: and the Perpendicular to
the 12 mile Post, 22. 50 chains.)

The angle made by our Line and the Radius Produced from Newcastle
is 89° 50* - Measured by a Hadley's Quadrant.

* To prove that the Chain Carriers had made no error
in the measurement of this 22. 51 Chains; I took a
man with me, a few days after, and measured it myself;
and made it within a Link of the same.

NB We set out from the Middle Point (as observed in the minutes of the 25th of June)
in the direction that the surveyors before run their 3rd Line; what
our Line varies from theirs to the Westward may be seen by the
following Table.

Mile Post

Chains and Links to
the West of Theirs

0

0

00

1

0

01 nearly

5

0

16. 5

10

0

58

15

1

24

20

2

13

25

3

14

30

4

40

35

5

55

40

6

46

45

7

30

50

8

17

55

8

98

60

9

80

65

10

86

70

12

14

75

14

00

80

16

25 and

This we measured at every 5 Mile Post at
Right angles to our Line as we came up.

17 chains 25 links. This was in the
direction of the Radius from Newcastle.

76

60

1764

June

26

29

July

1

2

Observations made in Running the Tangent Line

Attempted to take the passage of some stars (near the North Pole) over the
direction of the Line, but nothing was done with certainty.

Time of Watch

Equal altitudes of Alpha Coronae Borealis

h m

s

h

m

s

15 1

56

16

7

16

3

50

9

12

5

48

11

5

Then cloudy

(Sunday)
17 17

3

18

15

37’

20

33

19

45

24

48

23

26

19 9

48

20

57

40

12

00

21

00

12

14

40

00

2

32

Equal altitudes of Alpha Ophiuchi

For the Surveyors Offsets from their third or last Line

They were 5 chains 26 links to the West when at Right Angles nearly to the Point
12 Miles from Newcastle and then 81 miles about 7 chains from the Middle Point

Miles 80

1.9030899
2.7209857
4.6240756
1.9133051
2. 7107705

links

75

1. 9030899

2.7209857

4.6240756

1.9133051
1.0750613

2.7209857
4. 5960470

1.9133051
2.6827419

4.82

30

1.4771212

2.7209857
4.1981069

1.9133051
2.2848018

70

1. 9030899

2.7209857

4.6240756
1. 9133051
1.8450980

2.7209857
4.5660837

1.9133051
2.6527786

4.49

35

1. 5440680

2.7209857
4.2650537

1.9133051
2.3517486

65

1.9030899

2.7209857

4.6240756

1. 9133051
2.7107705
1.8129134

2.7209857
4.5338991

1.9133051
2.6205940
4. 17

5

0.6985700

2. 7209857
3.4195557
1. 9133051
1.5062506

60

1.9030899
2. 7209857

4.6240756

1.9133051
2.7107705

1. 7781513

2.7209857
4.4991370

1.9133051

2. 5858319

3. 85

1.93

32.

1 links

as 81 miles 78 chains 25 links: 22 chains 50 links: ;

80 miles : (x miles)

. •. 81. 978 (miles) : 2250 Links : : 80 :

(x)

80 miles

75

70

65

60

55

50

45

1.9030899

1.8750613

1.8450980

1. 8129134

1.7781513

1.7403627

1.6989700

1.6532125

3.3521825

3.3521825

3.3521825

3.3521825

3.3521825

3.3521825

3.3521825

3.3521825

5.2552724

5.2272438

5.1972705

5.1650969

5.1303338

5. 0925452

5.0511525

5.0053950

r 1. 9136973

1.9136973

1.9136973

1. 9136973

1.9136973

1.9136973

1.9136973

1.9136973

3.3415751

3.3135465

3.2835732

3.2513996

3.2166365

3.1788479

3.1374552

3.0916977

21.96

20.58

19.21

17. 84

16.47

15. 10

13.72

12.35

40 miles

35

30

25

20

15

10

5

1.6020600

1.5440680

1.4771212

1.3979400

1.3010300

1. 1760913

10000

0.6989700

3.3521825

3.3521825

3.3521825

3.3521825

3.3521825

3.3521825

11825

3.3521825

4.9542425

4.8962505

4.8293037

4.7501225

4.6532125

4.5282738

11825

4.0511525

1. 9136973

1.9136973

1. 9136973

1.9136973

1.9136973

1. 9136973

16973

1.9136973

3.0405452

2.9825532

2.9156064

2. 8364252

2. 7395152

2.6145765

2.1374552

10.98

9.61

8. 23

6. 86

5.49

4. 12

1.37

These are our offsets to the East of our 1st Line

79

61

From the foregoing taking the distance of the Post (fixed 12 miles from Newcastle)
from our line 22. 50 chains when at Right Angles (98° 50' making no sensible error)
at the distance from the Middle Point 81 miles 78 chains 25 links our offsets to the
Eastward will be as follows.

Miles from the

Offsets

From the Post (12 miles from Newcastle) to the

Middle Post

Eastward

Mark the Surveyors left in their line.

at nearlv

Miles

Chains

Links

Chains

Links

right angles with the Post is 5.

, 26 chains.

81

78

25

22

50

Hence their offsets to the East will be

80

21

96

75

20

58

Miles from the Offsets

Hence from the NB in the

70

19

21

Middle Point EAST

last page

, their offsets

65

17

84

Miles

Chains Links Chains

Links

from our Line will be at

60

16

47

81

75 00 5

26

Miles

Chains

Links

55

15

10 At

(80

5

14

80

21

39

50

13

72 milesyS

4

82

75

18

82

45

12

35

(70

4

49

70

16

63

40

10

98

65

4

17

65

15

03

35

9

61

60

3

85

60

13

65

30

8

23

55

3

53

55

12

51

25

6

86

50

3

20

50

11

37

20

5

49

45

2

88

45

10

18

15

4

12

40

2

56

40

9

02

10

2

74

35

2

25

35

7

80

5

1

37

30

1

92

30

6

33

0

0

00

25

1

60

25

4

74

20

1

28

20

3

41

15

0

96

15

2

20

10

0

64

10

1

22

5

0

32

5

0

48. 5

0

0

0

0

0

0

From the above our offsets will be to
the EAST of the offsets made by the third

or last Line at *

Miles

Chains

Links

80

0

57

75

1

76

70

2

58

65

2

81

60

2

82

55

2 „

59

50

2

35

45

2

17

40

1

96

35

1

81

30

1

90

25

2

12

20

2

08

15

1

92

10

1

52

5

0

89

0

0

00

Set off the 80 miles offset.
Waited for the Waggon, etc

(Sunday)

62

1764

September

4 The Waggons not returning, we set out on our return toward the Middle Point to make

our offsets at every 5th Mile Post as per Table marked *. This day set off the 75th Mile offset.

5 Set off the 70 and 65 Mile offsets.

6 Ditto: the 60, 55 and 50 Mile (offsets)

7 Ditto: 45 and 40 Mile (offsets)

8 Ditto: 35, 30 and 25 Mile (offsets)

9 (Sunday) Ditto: 20, 15 and 10 Mile (offsets)

10 At Mr. Twiford's on the banks of the River Nanticoke

11 Ditto

12 Ditto

13 The Waggons with Tents, etc. came to Mr. Twiford's

Thursday the 13th of September; went to see Pocomoke Swamp; Its about 30 Miles in Length
and 14 in breadth: (The West Line from the Sea to the Middle Point passes through it): There
is the greatest quantity of Timber I ever saw: Above the Tallest Oak, Beech, Poplar, Hickory,
Holly and Fir; Towers the lofty Cedar: (without a Branch), till its ever green conical top; seems
to reach the clouds: The pleasing sight of which; renewed my wishes to see Mount Lebanon.

14 Engaging ax men, providing Boards for marks, etc.

15 Ditto

16 (Sunday)

17 Went to the 10th Mile Post, and began to find a direction for the

Visto that should pass through our offsets.

18 Ditto. Set up three marks, one near the 10 Mile Post, one half a mile
North of it, and the other one mile South.

19 Found the Three Marks were not in a right line, but on moving the Middle one
half an Inch (East) the three marks made a right Line.

20 Run the Line down towards the Middle Point, about two miles.

21 Continued Ditto: and crossed the River Nanticoke at 6 miles, one chain and 92 Links from
the Middle Point, found we were to the West, of what we should be (according to the 1st
Line) five inches.

22 Continued Ditto: to the 5th Mile Post, etc., and found we were
ten inches to the West of the 5 Mile offset.

23 (Sunday)

24 Continued the Line to the 3 Mile Post.

25 Continued Ditto to the Middle Point and found we were two feet two inches to the West of the
said Point, This difference being so very small in the Radius of 10. 5 miles its correction
would bear no proportion to the loss of time on the part of the Honorable Proprietories, we
therefore resolved to return to the 10 Mile Post and continue the direction towards the

12 Mile Post from Newcastle.

26 Returned to Mr. Twifords.

27 Began in our former direction and continued the Line to the 13 Mile Post.

28 Continued the Line to 15 1/2 and found we were at the 15 Mile offset 4 Inches to the Eastward.

29 Continued the Line to about 17 Mile Post.

30 (Sunday)

October

1 Continued the Line to the 20 Mile Post, and measured the distance of our Line
from the Offset and found we were four feet Eight Inches to the Eastward.

2 Continued the Line to the 22 Mile Post

3 Continued Ditto: to the 24 Mile Post

4 Continued Ditto: to the 26 Mile Post nearly, and Measured the Distance of our Line from

the 25 Mile offset, and found we were Seven feet four Inches to the Eastward.

5 Continued the Line to the 28 Mile Post

6 Continued Ditto: to the 30 Mile and Measured the distance of our Line from
the offset, and found we were Eight feet three Inches to the Eastward.

7 (Sunday) Set out for Col. Lloyd's

8 Returned from Ditto.

9 Continued the Line to the 32 Mile Post

10 Continued Ditto: to the 34 Ditto:

11 Continued Ditto: to the 36 Mile Post and Measured the distance of our Line from

the 35 Mile offset, and found we were Seven feet and six Inches to the Eastward of the offset.

12 Continued the Line to the 38 Mile Post.

13 Continued the Line to the 40 Mile Post and found we were Eight feet five Inches

to the Eastward of the offset.

81

83

63

1764

October

14 (Sunday)

15 Continued the Line opposite the 42 Mile Post

16 Continued the Line to the 44 Mile Post

17 Continued the Line and measured the distance of our Line from the 45 Mile offset

and found we were Nine feet six Inches to the Eastward of said offset.

18 Continued the Line to the 46 Mile

19 Continued Ditto to the 48 Mile Post

20 Continued Ditto to the 50 Mile offset nearly.

21 (Sunday)

22 Continued the Line to about the 52 Mile Post. Measured the Distance of our Line from

the 50 Mile offset, and found we were Ten feet Eleven Inches to the East of the said offset. 84

23 Continued the Line to opposite the 54 Mile Post nearly

24 Continued Ditto to the 55 Mile Post nearly

25 Continued Ditto to about the 57 Mile Post and Measured the Distance of our Line from
the 55 Mile offset and found we were Eleven feet one Inch to the Eastward.

26 Continued Ditto opposite the 59 Mile Post

27 Continued Ditto to the 61 Mile Post and Measured the distance of our Line

from the 60 Mile offset and found we were distant therefrom. Ten feet six Inches Eastward

28 (Sunday)

29 Continued the Line to the 62 Mile Post

30 Continued Ditto to about the 63rd Mile Post

31 Continued Ditto to the 66 Mile Post and measured the Distance of our Line

from the 65 Mile offset and found we were Eleven feet seven Inches to the Eastward
November

1 The fogs and mist so thick that we could not proceed.

2 Weather Ditto. Attended the Commissioners at George Town.

3 Weather still so thick that we could not proceed.

4 (Sunday) 85

5 Continued the Line

6 Continued the Line and measured the distance of the 70 Mile offset and
found we were Twelve feet Eleven Inches to the Eastward of the offset.

7 Continued the Line

8 Continued the Line and measured the distance of the 75th Mile offset and found we
were fifteen feet seven Inches to the Eastward of the said offset.

9 Continued the Line to the 80 Mile offset and Measured the distance of Line
from the said offset and found we were Sixteen feet seven Inches to the Eastward.

10 Continued the line to the Point shown us to be the Tangent Point (in the Direction of the

Radius of 12 Miles from Newcastle mentioned in the Minutes of the 25th and 27th of

August) and measured the distance of our line from the said Post or Point, and found
we were Sixteen feet and Nine inches to the Eastward of the said Point. We also
continued our line 52. 5 yards when it was opposite the Post marked 3 S 1 and found we
were Sixteen feet from the said Post Eastward. We continued our Line 41. 5 yards
farther and then we were opposite the Post marked T P. We measured the distance
of our Line from the said Post and found we were fifteen feet two inches and a half

to the Eastward. 86

10 These three Posts were settled by the former surveyors and supposed to be in
the Periphery of the circle round Newcastle. Discharged the ax men.

11 (Sunday)

64

1764

November

12 Sent two Expresses, viz, one to his Excellency, Horatio Sharpe, Esq., Governor of

Maryland, and the other to the Honorable James Hamilton, Esquire, to acquaint them we
finished our second Line on Saturday last.

From the foregoing our second or last Line falling two feet two inches to the West

of the Middle Point, and Sixteen feet nine Inches to the East of the Point esteemed or

shown us to be the Tangent Point we have the Point of intersection where our second

Line crossed the true Line thus as 16 ft. 9 in. + 2 ft. 2 in. : 82 miles : : 2 ft. 2 in. : 9, 39 miles

Hence the true offsets of our second Line at every 5 Mile Post as follows.

Miles from the
Middle Point
0
5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

82

Offsets in
Feet Inches

2 2 ( To the Eastward of

1 0 \ our second Line

0

1

2

3

4

5

7

8
9

10

11

12

14

15

16
16

To the Westward of our second
Line for to give the Tangent
Line from the Post shown us to be
the Tangent Point.

Our measurements fromthe offsets of our first Line being

collected are as of the following Table

Miles from the
Middle Point

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

82

Our second Line
from the Offsets
Feet Inches
2 2 (

0 10 ( Westward

65

1764

November

12 From the two last Tables we have the difference of the Results
of our two Tangent Lines as follows at every five mile Post.

Miles from the

Feet

Inches

Middle Point

0

0

0

5

0

2

10

0

2.2

15

1

0

From the whole we consider that the offset Posts

20

2

2

made from our first Line standing in our

25

3

8

second Visto are (as near as practicable)

30

3

5

in the true Tangent Line.

35

1

7

40

1

4

45

1

3

50

1

6

55

0

7

60

1

2

65

1

3

70

1

1

75

0

5

80

0

3

82

0

0

13 From the Data in minutes of the 27th of August we computed how far the true Tangent Point
would be distant from the Post (Shown us to be the Tangent Point) and found it would not
pass one inch to the Eastward or Westward.

On measuring the angle of our last Line with the direction from Newcastle it was so near
a right angle, that, on a mean from our Lines, the above mentioned Post is the true Tangent Point.

From the whole we conclude that the offset Posts in our last Visto marked MD are
(or near as is practicable) in the true Tangent Line,

14

15

16

17 Waiting for the Commissioners

18 (Sunday)

19

20

21 The Commissioners of both Provinces met at Christana Bridge in the county of Newcastle.

22 Attended the Commissioners at Ditto.

23 At this meeting the Gentlemen Commissioners came to a resolution that what

24 we had done relating to the Lines should stand as finished.

25 (Sunday)

26 Discharged all hands and left off for the winter season. Returned to Mr. Harlands in the
Forks of Brandywine.

December

4 Wrote to the Honorable Proprietors to acquaint them we have finished the Tangent Line. 89

1765

January

10 Left Brandywine and proceeded to Lancaster (distance about 35 miles) a Town in Pennsylvania,
distant from Philadelphia 75 Miles, bearing nearly due West. What brought me here was my
curiosity to see the place where was perpetrated last Winter the Horrid and inhuman murder
of 26 Indians, Men, Women and Children, leaving none alive to tell. These poor unhappy
creatures had always lived under the protection of the Pennsylvania Government and had Lands
alloted for them a few Miles from Lancaster by the late celebrated William Penn, Esquire, Proprietor.

They had received notice of the intention of some of the back inhabitants and fled to the Gaol
(jail) to save themselves. The keeper made the door fast, but it was broken open; and two
men went in and executed the bloody scene; while about 50 of their party sat on Horse Back without;
armed with Guns, etc. Strange it was that the Town though as large as most Market

Towns in England, never offered to oppose them, though its more than probable they on request

might have been assisted by a Company of his Majesties Troops who were then in the Town.

no honor to them! What was laid to the Indians charge was that they held a private correspondence
with the Enemy Indians; but this could never be proved against the men and the women and children
(some in their Mothers wombs that never saw light) could not be guilty.

Wrote a letter from hence to Mr. Kingston^

66

1765

January

17 Returning at Pechway, I fell in company with Mr. Samuel Smith who in the year 1736

was Sheriff of Lancaster County, now three counties, Lancaster, York and Cumberland,
who informed me that the People near the supposed Boundary Line were then at open war.
About ten miles from Lancaster on the River Susquehanna one Mr. Crisep defended his
house as being in Maryland, with 14 Men, which he surrounded with about 55. They
would not surrender (but kept firing out) till the House was set on fire, and one man in the
House lost his life coming out.

19 At Brandywine

February

11 Left Brandywine and proceeded for New York.

13 Crossed the River Schuylkill near the Swedes-ford and lodged at Mr. McLanes Commissary
for the Lines,

14 Passed the Delaware (about 1/4 mile wide) on Ice: my Horse near being lost.

15 Passed through Prince Town in the Jerseys; here is the most Elegant built Colledge I

have seen in America. Lodged at Brunswick.

16 Passed through Elizabeth Town, crossed the River in to Staten Island, and over the Bay

(about 10 miles wide) to New York.

17 (Sunday) At New York . (Actually recorded as York).

18 At Ditto.

19 Ditto. Wrote to Mr. Williams.

20 In Long Island

21 Returned to Staten Island and took the Eastern Road; down for
Perth Amboy in the Jerseys.

22 t Passed through the Freeholds, Mount Pleasant and Mount

23 J Holly in the Jerseys. ^ .

24 (Sunday) Met some boys just come out of a Quaker Meeting House as if the De(vi)l had been
with them. I could by no means get my Horse by them. I gave the Horse a light blow on the
Head with my whip which brought him to the ground as if shot dead. I over his Head, my hat
one way wig another and whip another, fine sport for the boys. However I got up as did my
Horse after some time and I led him by the Meeting House, (the Friends pouring out) very
serene, as if all had been well. But

25 Lay too - my Hip being hurt very much by the fall.

26 Crossed Racoon Creek,

27 (Crossed the River Delaware to Newcastle and went to Newark (Delaware).

(Undated)

16 ft. 9 in. + 2 ft. 2 in. : 82 miles : : 2 ft. 2 in.
second line with the true line.)

Hence the offsets of our second Line

9. 39 miles (The point of intersection of

Miles from the
Middle Point

Feet

Inches

0

2

2 1

5

1

0 f

10

0

2 . 2

15

1

4

20

2

6

25

3

8

30

4

10

35

5

11

40

7

1

45

8

3

50

9

5

55

10

6

60

11

8

65

12

10

70

14

0

75

15

2

80

16

4

82

16

9

To the East of the Second Line

To the Westward

90

91

92

67

(Undated) Given LP = 6558. 31 (chains)

LN = 982. 51 (chains) To find PN

Angle PLN = 89° 50

LP = 6558.31
LN = 982.51

Sum = 7540.82
Difference = 5575. 80

(log 7540.82)
(log 5575. 80)
Log Tang 45° 05

(log tan) 36° 33' 35"
45 5 0

81 u 38 35"

= 3.8774186
= 3.7663072
= 10.0012633
13. 7475705
■ 9.8701519

= Angle LNP

As (log) sin LNP_ 81° 38' 35" =

: (log) LP 655831
: : (log) Sine 89° 50 1 PLN

: PN 6628. 67

As (log) PNHypot 6628.67
Rad

(log) NQ 960 chains
•**(log) Sine of angle QPN 8° 19» 38"
Complement angle QNP 81° 40' 22"

Angle LNP 81° 38' 35"
Angle LNQ 1 ’ 47 ”

: 9.9953639

3. 8167920
9. 9999982
13. 8167902
3.8214263

3.8214263

10 .

2. 9822712
9. 1608449

rArml , 47 " = PNQ Complement 89° 58' 13" = (Angle) NRO

(Angle) QRN = Complement 89° 58' 13" ^ngiej inkq

As Sine QRN 89° 58' 13"

: QN 960. 00
Rad

to Hypotenuse RN 960, 1/46 of a link

9.9999999

2.9822712

10 .

2.9822713

180° 00' 00"

_ 1 47 = (Angle) RNQ = (Angle) BNQ

179Q 58' 13"

89 59 06 = One half = Angle NBQ = Angle BQN
as (log) Sine 89° 59' 6" (Angle) NBQ 10. 0000000
to (log) QN 960. 00 io QQ09710

:: dog) Sine PNQ !■ 47" 6 7149^6

: BQ 0.498 chains 9.6972298

Therefore 0 chains 50 Links to be set off with an angle of 89° 59' 06" = Angle QBN
(Paper frayed). Point B from the direction BN from Newcastle.

Figure

93

68

(undated)

As Sum

(logarithms)
3. 8774186

to Difference

3.7163072

Tangent 45° 2. 5

10.0006317

36° 31' 11"

13.7469389
9.8695203

45 2 30

81° 33' 41" (log) Sine

9.9952864

LP = 6558.31

3.8167920

PLN 89° 55' (log) Sine

9.9999995

PN 6629.87

13.8167915

3.8215051

(log) PN

3.8215051

(log) R

10.

(log) NQ

2.9822712

(log) Sine 8° 19' 32" = QPN*

9.1607661

QNP =
LNP =
QNR =
QRN =

90 u

81° 40' 28"
81° 33’ 41"

6

89© 53
(log) 960. 00

47"

13" = (log) Sine

(log) 960

9.9999991

2.9822712

10 .

2. 9822721

94

1764

June

26

29

July

1

From the Angles and Radius NQ and QN = SQ
is had, then to find dl, op, etc.

Set SI = any measured distance : then

QS - SI = IQ = Ng and also

lg = QN. hence in the Triangle

dNg given dN = 12 = Rad. and gN

find the perpendicular dg. Then dg - lg = dl = what

is to be laid off at Right Angles to the Meridian

Observations for determining the time of stars passing the Azimuth corresponding to
our first Line from the Middle Point to the twelve Mile Post from Newcastle .

(Sunday)

Time of Watch

h

15

m

s

h

m

s

Attempted to take the passage of some stars near
the North Pole, but nothing was done with certainty *

1

56

16

17

16)

3

50

9

12 1

f Equal altitudes of Alpha Coronae Borealis

5

48

11

Then Cloudy

16

9

50

_

_ _ _

. - -

22

25

\ Equal altitudes of Antares Right Ascension « 16* 1 15 m I s

* "

” ■* *

“ * *

17

0

47

j (on) August 1, 1764

19

44

22

—

- -

)

57

10

20

4

15

>Ditto of Alpha Aquilae Right Ascension = 19* 1 39 m 18 B

22

23

20

16

50 ,

} (on) August 1, 1764

46

1st wire of Telescope

22

46

50

Middle Ditto

(The star next the Pole Star in the Tail of the

23

14

46

Third Ditto

\ Lesser Bear, passed in the direction of the Line,

69

1764

July

2

4

5

6

Time by the Watch

h

m

s

h

m

s

17

17

3

18

15

37)

20

33

19

45

► Equal altitudes of Alpha Ophiuchi

24

48

23

26)

19

9

48

20

57

40)

12

00

21

00

12

* Equal altitudes of Alpha Aquilae

14

40

2

32)

Cloudy when the star next the Pole Stab in the Tail of the Lesser
Bear passed the direction of the Line.

15

52

36

17

18

32 |

57

55

24

45 > Equal altitudes of Ant ares

16

4

4

30

30 )

19

27

58

20

36

551

31

28

40

55 f Equal altitudes of Alpha Aquilae

35

30

44

28)

Cloudy

19

32

40

20

36

57 |

36

24

41

12 / Equal altitudes of Alpha Aquilae

40

34

46

50 )

22

32

10

1st wire

55

10

Middle

The star next the Pole Star in the Tail of the Lesser

Bear passed the direction of the Line.

23

28

10

Alpha Ursae Majoris under the Pole Star.

7

14

15

7

45

30) Equal altitudes of Sun's upper Limb

18

12

50

56)

23

34

Sun's center passed the Meridian by the Watch 7h 34m 33s

Sun's Right Ascension at this time (the dif¬

ference of the Meridian from Paris by the Lunar

Eclipse of March 17th) = 5h 14m 41s 7 4 55

> Watch too fast for Sidereal Time Oh 29m 38s

19

26

30

20

48

5 1

29

32

51

15 / Equal altitudes of Alpha Aquilae

32

48

54

18)

Cloudy 1st wire and middle
23 26 00

Ditto

The star next to the Pole Star passed by third or
Alpha Aquilae passed the Meridian by the Watch
This star’s Eight Ascension
Watch too fast for Sidereal Time

last wire ’
20h 10m 25s
19 39 18

31m 37s

The star in the Tail of the Lesser Bear passed the last wire at

Time in passing from the Middle wire to the last by observation 1st July

Star at the Middle Wire, that is, in the direction of the Line

Watch too fast at this time

Right Ascension of the Mid Heaven

time of the star next the Pole Star in the tail of the Lesser Bear passed
an Azimuth in the direction of the Line.

23h 26m 00s
27 56

22h 58m 04s
31 30

22h 26m 34s at the

15

49

00

17 5

10

I Equal altitudes of Antares, hence passed at

16h 33m 36s

55

00

12

17

>

16 15 01

16

2

8

18

3;

^ Watch fast

18m 35s

19

29

26

20 15

361

1

34

18

21

4°

; Alpha Aquilae, hence this star passed at

19h 57m 58s

40

21

26

30 J

\

19 39 18

Watch fast

18m 40s

22

21

30

1st wire

)

The star next the Pole Star in the Tail of Ursae Minoris

44

45

Middle

passed the Azimuth of the Line.

23

12

35

Third

)

12

35

Star passed the Azimuth at

22h 44m 45s

Watch faster than by the above star 18 44

Right Ascension Mid Heaven when the star passed 22h 26m 01s
the Azimuth

96

97

70

Time by the Watch

July

h m

s

h m

s

11

7 17

55

7 49

42

21

38

53

45

26

37

58

48

30

35

8 2

30

19

33

7

20 42

36

48

46

40

50

50

22

35

40

1st wire

58

15

Middle

23

26

10

Third

Equal altitudes of Sun's upper Limb

Ditto. Sun's Lower Limb

Hence the Sun passed by the Watch at

Right Ascension of Sun

Watch fast

Antares,. Hence Antares passed at
Right Ascension Antares

Watch fast

The motion was very slow

Alpha Aquilae. Hence star passed at
Right Ascension

Watch fast

The star next the Pole Star in the Tail of Ursae Minoris

7h

40m

11s

7

25

20

14m

51s

16h

47m

48s

16

15

1

32m

47s

2 Oh

11m

49s

19

39

18

32m

31s

very dubious

From the last wire
Subtract time from middle

23h 26m 10s
27 56

22h 58m 14s

19

19

00

clouds

)

Equal altitudes of

21

35

21 2

40 }

Right Ascension

24

25

5

18)

22

36

3

1st wire

58

50

Middle,

cloudy till a little past.

23

27

00

3rd wire

Watch fast 32m 18s

Right Ascension Mid-Heaven 22h 25m 56s
when the Star next the Pole
Star passed the Line

Watch fast

by observation on the
1st of February
Star next the Pole Star
passed the direction of the
Line

20h 12m 8s
19h 39m 18s
32m 50s

By observation on 1st
of July from the first

The Star next the Pole Star in the Tail of
Ursae Minoris passed the Direction of the Line.

wire to Middle

23

4

and from middle wire to third

27m 56s

Ch the 5th of July

23

0

Ch the 10th

23

15

and 10th Ditto

27

50

Mean

23

6

Mean

27

53

Passed the 1st wire above

at

22

36

3

Passed above

23

27

00

Middle wire at

22

59

9

Middle at

22

59

7

By the first wire

59

9

Mean

22h

59m

8s

The time by the Watch when the star passed the Direction of the Line.

Equal altitudes of Sun's upper Limb

Hence Sun passed the Meridian at 8h 56m 21s
Right Ascension of Sun 8 25 26

Watch fast 30m 55s

Watch fast when Alpha Aquilae pas sed 32 50

. lm 55s

Then as 12. 2 : l r

which subtract from

Watch fast when star passed the Line
Passed the Middle wire at time above
Right Ascension Mid-Heaven when star passed the
direction of the Line on the 25th, that is this morning

32m 50s
0 26
32 24

22 59 08

22h 26m 44s

71

1764

Time by the

Watch

July

h

m

s

h

m

s

27

18

10

45

19

45

4

11

54

46

10

12

56

47

11

20

33

58

21

30

50

35

33

32

23

37

3

33

58.

22

34

7

1st wire

57

36

Middle

24

19

3rd wire

30

August

17

27

‘ Equal altitudes Alpha Lyrae
Zenith Distance about 11°.

Equal altitudes. Alpha Cygni
Zenith Distance, 8°

* Azimuth in the direction of the Line
Watch fast when star passed the Direction
Star passed at

Right Ascension mid-heaven

h

m

s

Hence this star passed at

18

59

00

Right Ascension

18

28

58

Watch fast

30

2

Hence this star passed at

21

3

58

Right Ascension of Star

20

33

25

Watch fast

30

33

passed

31m 01s
22h 57m 36s
22h 26m 35s

18

03

40

20

2

50)

33

42

--

34

55

4

59)

56

12

21

49

13 1

57

56

50

52 /

59

36

52

26)

23

18

25

Middle wire.

99

Equal altitudes. Alpha Lyrae. Hence this star passed at

Right Ascension
Watch fast

49 131

50 52 > Equal altitudes. Alpha Cygni. Hence this star passed at

52 26 ' Right Ascension

Watch fast

Star passed the direction of the Line.

Star in the Tail next the Pole star passed the direction

of the Line
Watch fast

Right ascension mid-heaven when the star crossed the

line

18

47

25

19

—

—

48

24

37

00

49

33

38

00

20

42

45

21

50

48

44

8

52

12

45

30

53

30

23

12

48

Middle

Equal altitudes. Alpha Lyrae.

Equal altitudes. Alpha Cygni

Hence this star passed at
Right Ascension
Watch fast

Hence this star passed at
Right Ascension
Watch fast

18

54

38

19

58

50

55

40

59

54

56

44

20

0

57.

21

6

32

21

54

46;

8

4

56

25

9

44

58

2,

23

25

55

direction of the Line

Star in the Tail passed at
Watch fast at this time

Right ascension, mid-heaven when the star passed

the Line

Equal altitudes of Alpha Lyrae.Hence the star passed at

Right ascension
Watch fast

Equal altitudes of Alpha Cygni. Hence the star passed at

Right ascension
Watch fast

The star in the Tail of Ursae Minoris passed the directic
Star in the Tail passed at
Watch fast at this time

Right ascension mid-Heaven when star passed the Line

h

19

18

m

18

28

s

51

58

49

53

21

24

23

20

33

25

50

58

23

18

25

51

57

22

26

28

19

12

42

18

28

58

43

44

21

18

9

20

33

25

44

44

ed the

23

12

48

45

39

22

27

9

19

27

47

18

28

58

58

49

21

32

31

20

33

25

59

6

n of the Line

23

25

55

59

21

22

26

34

100

72

(Undated)

For the angle the 1st and middle wires make in the Transit Instrument

(logarithm)

as AC 335.94 12. 5262617

: R 10.

: : 1. 1666 .. 10.0669220

: Tang. Angle BAC 12* 00 7.5406603

= Angle of the two wires, and the time of the star in the Tail
of Ursae Minoris, passing this angle as follows by
different observations.

on July 1st

23'

4'

5th

23

00

10th

23

15

27th

23

29

Mean of 12 minutes 23 1 12” and this time the star is passing an angle of 12' 00’

(Then follow two sets of logarithmic calculations which were deleted)

N. B. The method of finding above the angle subtended between the first and middle wires
was thus - A mark BC was placed at such distance that the wires bisected the
points B and C: Then BC being measured it was = 1. 1666 feet and the
distance from the Instrument at A, to C = 335. 94 feet; hence the Angle
BAC = 12' 00" as above.

(Undated)

The foregoing Observations were made with the Transit Instrument
in the following manner.

Before we left off in the Evening a mark was placei at the distance

of 1/2 or 3/4 of a mile in the Line Northwards : Then after the equal altitudes

were observed, the Instrument was adjusted as when we gave off. Then a

candle being placed in the center of the Mark; the middle wire in the

Telescope was brought to bisect the light of the candle. (The line of collimation

being just, and the Level proving the Horizontal position of the axis.) Then the Telescope

being elevated to the Star, the time (by the watch) of the stars passing the

middle wire (with which the Line was run) was taken.

The Watch with which these observations were made, had only the Hour
and minute Hands; therefore the seconds must not be expected as from
a good time Piece, nor does the nature of the Problem require it, as the
star made use of, (Delta Ursae Minoris) was at the time of observation nearly
passing the Tangent of its circle around the Pole. Consequently its apparent
motion (was) very slow.

1765

March

i Began to prepare for running the Western Line: the method of proceeding as follows.

Let P be the Pole, ABCD the Parallel of Latitude to be drawn.

AC the arch of a great circle. At pleasure suppose = 10 minutes

(which we shall set out with on the first station, and in order to

find the direction AC, there is given in the Right Angled Spherical Triangle EPA

AP = Complement of Latitude = 50° 16’ 421*61 Hence Angle PAE = 89° 55' 51" =

AE = One-half AC = 5’ )

the angle from the North Westward : and to lay off this angle with.the
Transit Instrument by the Stars; Let P be the Pole
Z the Zenith and S the place of the star. Then in the oblique angled
Spherical Triangle SPZ, there is given
SP = the stars distance from the Pole
ZP = the Complement of the Latitude

Angle SZP = 89° 55' 51" = the star's azimuth from the North when it will
be on the direction AEC above. To find the angle SPZ or angle at the
Pole when the star is on the said azimuth.

1765

March

1 The angle SPZ being added to the star's Right Ascension: if to the Westward of the meridian
or subtracted if the Star is to the Eastward; gives the Right Ascension of the Mid-Heaven,
when the star is upon the azimuth Required. In this manner the Right Ascension of the

Mid-Heaven for different stars is as follows.-Next to find by the clock when the star

will be on the said azimuth, two equal altitudes of the same star before the time are
observed, whence the time is gained. At this instant of time the Middle Wire is brought
to bisect the star, and in that position

(The axis of the Telescope, etc., being Horizontal) the vertical axis is made fast: Then
the Telescope is brought parallel to the Horizon, and a Mark set
by the help of a candle (at the distance of 1/2 or 3/4 of a mile) so that the
middle wire bisects it.

In this manner we proceed with 3 or 4 different stars and find that

at the distance of 1/2 a mile the extremes of the distances of the marks Figures a andb

made by the different stars will not in general exceed 5 or 6 inches. 103

The line AC being run with the Transit Instrument, at C we
set up the Sector to prove or correct the work, by observing the Zenith
Distances of the same stars that were observed at the point A.

At C, we find a new direction as before, etc., etc.

The greatest distance EB to be laid off from the right Line AEC when

AE = 5' is 17. 14 feet. 104

Computing the star Azimuths, etc., for the direction Westward
(Sunday)

Cloudy, Heavy rains, etc.

Made some observations to find the Direction and placed one mark at the
distance of one-half mile, etc.

Snow
Snow
Snow

(Sunday) At 9 in the Morning the Snow was two feet nine or ten
inches deep in general, where the wind had not the least effect to heap it.

Snow still so deep we could not proceed.

Made a few observations, but dubious.

Cloudy

Ditto. Messrs. Darby and Cope, chain carriers, came from the Lower Counties
(Sunday) Ditto

Cloudy
Ditto
Ditto

Made more observations for finding the direction West: See them in the 6th page following. 105

2

3

4

19

20

21

22

23

24

28

29

30

31

April

1

2

3

4

74

(Undated)

Aldebaran
h m s

4 22 291/2 Right Ascension in time, Aldebaran

4 22 28 1/2 or 29s and Distance to Pole = 73° 48' 56"4

o

Sirius
98 38 37

_ 3 32 (Precession)

98 42 9 = 6h 34m 49 s = Right Ascension Sirius

Note: These Right Ascensions, etc., are for the end of March 1765.

Castor

109

48

46

+5

5

109

53

51

Procyon

111 40

57

4

12

111 45

9

Pollux

112 39

4

4

55

112 43

59

198;

Spiea

8

44

4

8

19)8

12

52

Arcfoarrtms

211

10

43

+3

42

211

14

35

7h 19m 35. 5s = Right Ascension Castor
Distance to Pole = 57° 37' 12”

7h 27nx Is - Right Ascension Procyon, Distance to Pole - 84° ll r 15"

7h, 30m 55s = Kigfct Ascension- PoDuot
Distance to Ptede = SI® 25' 3

13h I2m 5I fc 5s = Right Ascension Spica. To Pole 99° 55' 44"

14h 4m 58s - Right Ascension Arcturus. Distance to Pole = 69° 34* 58 M

1760

Eta (Tauri) Pleiades - (Alcyone)

Right Ascension
530 is* 51”

+4 52

53° 23 1 43” = 3h 33m 35s = Right Ascension

Declination
23° 20' 40"
+ 1' 06"
230 21' 46"
Distance to Pole = 66° 38' 14"

106

75

(Undated )

Computations, etc. for finding the Direction

Latitude 39° 43' 18 M of the point 15 Miles South of Philadelphia

Complement 50 16 42 (log) comp. Sine = 0.1139879

10 00 (log) ditto Sine = 0. 1139879

Sum 100° 43' 24”

1/2 50 21 42 (log) Sine = 9. 8865061

Difference 0 5 0 (log) Sine = 7. 1626960

17.2772079 -20
8.6386039 -10

0. 1139879 0. 1139879

2.5362745 2.8373039

9.8865361 9.8865361

7.1626960 7.1626960

19.6994945 20.0005239

9.8497472 -10 = (log cos)

(Angle) = 44° 57' 55" x 2 = 89° 55' 50"

= Angle LBP

Aldebaran (log)

as Sine SP 73° 58'

56"

=

9.9828030

: Sine Z 89 55

50

=

9.9999997

: : Sine PZ 50 16

42

=

9.8860155
19. 8860152

: Sine ZSP 53° 9'

6 "

9.9032122

-10

(Pole to Star)

73°

58’

1 56"

(Pole to Zenith)

50

16

42

Difference

23°

42 1

, 14 "

Che-half =

11 °

51’

, 7 "

(log)

Angles

89°

55 1

1 50"

As Sine 1/2 diff. sides

n°

51'

7"

=

9.3125

53

9

6

: Tang 1/2 difference angles

18°

23'

22 "

=

9.5217278

Difference

36 u

46 1

, 44 »

: Sine 1/2 Sum of sides

62°

7'

49"

=

9.9464586

One-half =

18°

23 1

i 22 "

To CoTang 1/2 Angle P

34°

56'

51"

—

19.4681864
10. 1556210

Sum of the Sides =

124° :

15' 38"

Double

69°

53'

42"

SPZ

One-half -

62

o

7' 49"

in time

4h

39m 35s

Right Ascension Aldebaran

4h

22m 28. 5s

Right Ascension Mid-Heaven when Aldebaran passes the Azimuth

9h

2 m

3.

5s

Alpha Orionis

Right Ascension

=

850 3 7 »

3" - 5h 42m
(log)

28s Distance to Pole

= 82°

39' 41"
(log)

Sine

82°

39'

41" =

9.9964279

Sine

16°

11 '

30" =

9.4453729

Sine

89°

55'

51" =

9.9999997

Sine

66 °

28'

12 " =

9.9622988

Sine

50°

16'

42" =

9.8860155

19,8860152

Tang

19°

32’

23" =

9.5500047
19.5124035

Sine S

50°

51'

5"

9.8895873

CoTang

4 ^

o

c

35'

45"

10.0670306

Sides

o

CM

39'

41"

Difference =

32°

22 '

59"

2(40° 35’ 45") = 810 hi 30*

' = 5h 24m 46s

50°

16'

42"

One-half =

16°

11'

30"

Right Ascension =

5h 42m 28s

Sum

132®”

56'

23"

Right Ascension Mid-Heaven =

llh 7m 14s

One-half

66°

28'

12"

Angles

89°

55'

51"

when Alpha Orionis passes

50°

51'

5"

39°

4'

Te 7 '

Figures a, b, andc

One-half =

19°

32'

23"

107

76

(Undated) (log)

Rad 10. 0000000

Sine 50° 16’ 42" (PB) = 9. 8860155

Sine 89° 55' 51" = 9.9999997

Sine PZ 50° 16' 4U'83 = 9.8860152 here the difference

between PB and PL (=RL) being but 3 in the last place

as 175 : 10" : : 3 : . 171 of a second = 17.1 feet = RL

(Undated)

(Miscellaneous multiplication and long division, not transcribed)

148° 57'

47" =

9h

55m

51s = Right Ascension,

Regulus. Distance to Pole

= 760

(log)

As Sine

76°

53'

40"

= 9.9885384

Sine

89

55

54

= 9.9999997

Sine

50

16

42

= 9.8860155

19.8860152

Sine Angle at Star

= 9. 8974768 -10 Angle at Star = 52°

09' 36"

Sides

76°

53'

40"

Difference 26° 36'

58"

50

16

42

One-half 13 18

29

Sum

127°

10'

22"

Angles

890 55*

51"

Gie-half

63°

35*

11"

52 9

36

Difference

37° 46'

15"

One-half

18° 53'

7"

As Sine one-half difference Sides
: Tangent one-half difference Angles
: Sine one-half Sum of Sides

to CoTang 1/2 Angle P 36 u 55*

73° 50'

Right Ascension, Regulus
Right Ascension, Mid-Heaven

(log)

13° 18
18° 53

’ 18' 29" = 9.3620889

> 53' 7" = 9.534X397

> 35' 11" = 9.9521170

19.4862567
= 10.1241678

= 4h 55m 21s
= 9h 55m 51s

= 14h 51m 12s, when Regulus passes the Azimuth

Sine

69°

34'

58" =

9.9718217 Arcturus

Sine

89

55

51 =

9.9999997

Sine

50

16

42 =

9.8860155

Sine of (55° 9'

19. 8860152
9.9141935

69°

34'

58"

Difference 19 (

50°

16'

42"

One-half 9

Sum

119°

51’

40"

Che-half

59°

55'

50"

(log)

As Sine

9°

39'

8" =

9.2244486

Tang

17

23

14 =

9.4957331

Sine

59

55

50 =

9.9372263

19.4329594

To CoTang

31

44

44 =

10.2085108

63

29

28 =

4h 13m 58s

Right Ascension Arcturus *

14h 4m 58s

18' 16"
39 8

Angles 89° 55' 51"
55 9 24

34° 46' 27"
One-half 17” 23' 14"

Right Ascension Mid-Heaven 9h 51m 00s when Arcturus is in the Azimuth East

Figures a and b
110

77

(Undated)

Right Ascension 7h 27m Is Procyon to Pole 84° IV 15"

dog)

Sine

84°

11»

15"

=

9.9977613

Sine

89

55

51

=

9.9999997

Sine

50

16

42

=

9,8860155

19.8860152

Sine S

0

o

m

38'

10"

=

9.8882539

Sides

84°

11'

15"

Difference = 33°

54'

33"

Angles

89°

55'

51"

50

16

42

One-half = 16

57

17

50

38

10

Sum

134°

27'

57"

Difference

39°

17'

41"

One-half

67°

13'

58"

Qie-half

19°

38'

50"

dog)

Sine

16°

57'

17"

=

9.4648112

Tang

19

38

50

=

9.5526840

Sine

67

13

58

=

9.9647708

19.5174548

CoTang 1/2 (41

32

9)

=

10.0526436

830

4*

18"

=

5h 32m 17s

Right Ascension = 7h 27m Is

Right Ascension Mid-Heaven 12h 59m 18s when Procyon passes

Right Ascension llh 37m 5s Beta Leonis to Pole 74° 7* 1"

(log)

Sine 74°

7'

1"

=

9.9830948

Sine 89

55

51

=

9.9999997

(Editorial Note:

S is the angle at the star between

Sine 50

16

42

=

9. 8860155

the pole and the zenith.)

19.8860152

Sine Angle S 53° 6*

1"

=

9.9029204

Sides 74°

7'

1"

Difference

23°

50' 19"

.Angles 89° 55'

51"

50

16

42

One-half

11

55 10

53 6

1

Sum 1240

23'

43"

Difference 36° 49'

50"

Che-half 62°

11'

52"

Che-half 18° 24'

55"

(log)

Sine 11°

55'

10"

=

9.3149963

Tang 18

24

55

=

9.5223815

Sine 62

11

52

=

9.9467287

19.4691102

CoTang 1/2 angle

10.1541139

Che-half angle =

35°

2'

27"

Angle = 70°

4 1

54"

=

4h 40m

20s

Right Ascension

llh 37m

5 s

Right Ascension

Mid-Heaven 16h 17m

25s

when Beta Leonis in on the Azimuth

Figure

in

78

(Undated)

For the Direction to intersect the Parallel 10’ West by using stars to the Eastward

Right Ascension of Eta Pleiades = 3h 33m 35s, Polar Distance = 66° 38' 14 ,f
Here the Angle SZP = Comp, of AZP to 180° = 90° 4' 9", then as before

(log)

As Sine

66° 38'

14" =

9.9628485

(Editorial Note:

The star which Mason lists as

: Sine

90 4

9 =

9.9999997

Eta Pleiades appears to be Eta

; : Sine

50 16

42 =

9.8860155

Tauri p i, e. * Alcyone.)

: Sine Angle 2SF 56

54’ 50

M 9.9231667

Sides

66° 38’

14"

Angles 90° 4' 9"

50 16

42

56 54 50

Sum

1160 54'

56"

Difference

16° 21' 32"

Difference 33° 9‘ 19"

Che-half

58° 27'

28”

One-half

to

o

T—i

o

00

Che-half 16° 34' 40"

As Sine

o

H

o

00

1 46"

= 9. 1531250

: Tang 1/2 Diff 16° 34' 40"

= 9.4737652

Sine

580 27

28"

= 9.9305695

19.4043347

To CoTang 1/2 58° 33' 56 !t

= 10.2512097

Right Ascension = 3h 33m 35s

Right Ascension of the Mid-Heaven = 23° 39' 19" when Eta (Tauri) Pleiades is on the Azimuth East at

90° 4' 9" from North

Right Ascension Aldooaran 4h 22m 29s Polar Distance = 73° 58’ 55 M

(log)

As Sine

73°

58'

55"

= 9.9828030

: Sine

90

04

09

: : Sine

50°

16’

42"

: Sine of

53

09

06

90

4

9

Difference

36^

55'

3"

Che-half

ISO

27'

32"

Diff. Angles

(log)

As Sine one-half Diff. Sides 11° 51* 7" = 9.3125654

: Tangent 18 27 32 = 9. 5234833

: : Sine one-half Sum-Sides 62 07 49 = 9.9464586

19.4699419

CoTangent 34° 50' 20" = 10. 1573765

(Double Angle) = 69° 40' 40" = 4h 38m 43s

Right Ascension Aldebaran - 4h 22m 29s

Right Ascension Mid-Heaven * 23h 43m 46s when Aldebaran will be on the Figure

Azimuth 90° 4' 9” which Line produced west will cut the parallel at 10' West. 112

79

(Undated)

Right Ascension 28° 25* 28"

+4* 43"

28° 30' 11" = lh 54m Is, Alpha Arietis Polar Distance = 67° 39' 23"

As Sine

67°

39'

23" =

9.9661045

: (Sine)

90

4

09 =

9.9999997

: : (Sine)

50

16

42 =

9. 8860155-

19.8860152

(Sine) angle ZSP

56°

15*

n

CD

9.9199107

Sides

67°

39'

23"

Difference

17° 22' 41"

Angles

90°

04*

09"

50

16

42

One-half

8 41 20

56

15

46

Sum

1170

56'

“OSF

Difference

33°

48'

23"

Che-half

58°

58'

02"

One-half

16°

54'

12"

(log)

As Sine

8°

41'

20" =

9. 1791757

: Tangent

16

54

12 =

9.4827118

: : Sine

58

58

02 =

9.9329162

19.4156280

CoTangent 30° 07' 14" = 10.2364523

Double = 60° 14' 28" = 4h 00m 58s Figure

Right Ascension of Alpha Arietis lh 54m 01s

Right Ascension Mid-Heaven 21h 53m 03s when Alpha Arietis will be on the Azimuth

of 90° 04' 09" in the East 113

1765

April

m

s

h

m

s

h m s

h

m

s

34

27

10

54

56

20 35 18

10

17

38

Regulus

37

16

57

58

20 34 14

40

21. 5

Right Ascension of Regulus

9

55

52

Clock too fast

21

46

39

10. 5

45

18

12

12

43

23 58 01

11

58

58

Beta Leonis

12

18

40

3 57 50.5

Right Ascension Beta Leonis

11

37

5

Clock too fast

21

53

Hence

12

59

18

+

21

46

Clock gains

+ 12

IF

21

16 =

time by the clock when Procyon will be on the Azimuth

14

51

12

+

21

46

Clock gains

+

00

18

15

13

16 =

time by the clock when Regulus will be Ditto.

16

17

24

+

21

46

Clock gains

+

0

23

16

39

33 =

(Time) when Beta Leonis will be Ditto.

At these three different times we placed three marks at the distance

of about one-half mile. One mark was placed on the 20th of March. The extreme of the

distances of these four marks; that is

from the Northernmost of them to the Southernmost was 18 inches. 114

80

1765

June

1

1765

March

28

April

5

6

7

8

9

10

11

12

13

14

15

16

Right

R.

A. in time

Polar

Time when

Ascension

Distance

West or East

o

t

M

h

m

s

o

i

it

h

m

s

Aldebaran

63

37

22

4

22

29

73

58

55

9

2

3

West

Arcturus

211

14

47

14

4

59

69

35

02

9

51

1

East

Alpha Orionis

85

37

13

5

42

29

82

39

27

11

7

13

West

Procyon

111

45

25

7

27

1

84

11

16

12

59

18

West

Regulus

148

57

59

9

55

52

76

53

46

14

51

12

West

Beta Leonis

174

16

14

11

37

5

74

7

1

16

17

24

West

Sirius

98

42

31

6

34

50

Castor

109

54

06

7

19

36

Pollux

112

44

15

7

30

57

Spica

198

13

04

13

12

52

Time by

Clock

Passed

the Meridian

h

m

s

h

m

s

h

m

s

h

m

s

7

00

02

7

59

32

15

3

41

)

Equal altitudes

7

02

00

8

01

44+

15

3

44+

7

31

52-/

Pollux

7

04

09+

8

03

42

15

3

44

9

34

54

10

01

55

19

53

50

40

47+

12

45-

19

53

32 1

l 9

56

46

Regulus

51

55

18

37. 5

19

53

31. 5 J

r

11

08

08

Alpha Orionis'

>

13

00

13

Procyon

> Passed the Azimuth by the Clock

14

52

07

Regulus

1

;

1

15

28

59.5

16

52

07+

32

33

10 i

34

35

58

39

32

33

14 1

[ 16

16

36

Antares

41

03

17

04

10

32

33

9. 5 '

1

9

21

13

10

49

56

20

16

35 ]

1

23

49

52

47

20

16

36

10

08

18

Regulus

26

39

55

24+

20

16

37 J

i

Hence clock too fast 12m 26s

11

12

01

12

21

20

23

39

31 )

1

14

59

24

38

23

39

37

> 11

49

47

18

11

27

34. 5

23

39

35. 5 J

1 Hence clock too fast 12m 42s frc

these stars.

The clock will gain of siderial time 29 seconds from Regulus

passing the meridian to the time when Procyon will be in

the meridian, then 12m 26s + 29s = +12m 55s clock fast

or 12h 59m 18s + 12m 55s = 13h 12m 13s Procyon West by the clock

and Regulus will be West by the clock at 15h 04m 25s 115

Began to run the western Line in the direction of the mean of the four marks

Continued Ditto

(Sunday)

Continued Ditto. Crossed White Clay creek at the distance from the
Post marked West (15 Miles South of Philadelphia) one mile 58 chains
Continued Ditto

Continued Ditto. Crossed Little Christianna Creek at the distance from Ditto (Post
marked West) 3 Miles 25 chains. At 3 Miles 49 Chains went through Mr. Price's House.

Continued Ditto. Four Miles 9 chains to great Christianna Creek

Continued Ditto. Crossed the Greater Elk River at the distance of 5 Miles 65 Chains.

Crossed the Lesser Elk at 8 Miles 59 Chains.

Continued Ditto. Crossed the Road from Acterara to Christianna Bridge at

12 miles nine chains from the said Post

(Sunday)

Returned to the end of the Line for the Sector

Set up the Sector in our direction at the distance of 12 Statute Miles 25 Chains

from the Point where we began and made the following observations. 116

81

1765

April Plane of the Sector East

Star Name Nearest Point Revolutions and Difference Apparent

on the Sector Seconds on the Zenith

Micrometer Distance

0

i

M

R

• i

i

II

0

i

ii

16

Alpha Lyrae

1

10

-

14

36.5

0

56.0

1

9

4. 0 S

13

32. 5

17

Capella

6

0

+

9

22.5

0

42.0

6

0

42.0

8

32.5

Alpha Lyrae

1

10

-

5

3.5

0

55.0

1

9

5. 0

4

05

Gamma Cygni

0

15

-

4

11.0

2

14. 5

1

32.5

Alpha Cygni

4

45

1

10-

1

42.3

4

43

17.7

3

8

18

Alpha Lyrae

1

10

-

10

25

0

54.7

1

9

5.3

9

22+

19

Alpha Lyrae

1

10

-

9

1+

0

53.3

1

9

6.7

8

0

20

Capella

6

0

+

7

37

0

37.7

6

0

37.7 faint

6

51+

Alpha Lyrae

1

10

-

7

27

0

54.5

1

9

5.5

6

24. 5

Alpha Cygni

4

45

-

9

51.5

1

46.5

4

43

13. 5

12

2

21

(Sunday)

Capella

6

0

+

12

46.5

0

41. 5

6

0

41.5

12

5

Then turned the Instrument

Plane of the Sector West

21

(Sunday)

Alpha Lyrae

1

10

-

11

2.5

0

58.0

1

9

2.0

12

8.5

22

Cloudy

23

Capella

6

0

+

7

31.5

0

48. 2

6

0

48.2

8

28-

Alpha Lyrae

1

10

-

8

42

1

1

1

8

59.0

9

51

Alpha Cygni

4

45

-

6

33-

1

40. 7

4

43

19.3

4

36

in

24

Capella

6

0

3

32.5

0

44.5

6

0

44.5

4

25

Alpha Lyrae

1

10

-

8

31+

0

59.7

1

9

0.3

9

39

Alpha Cygni

4

45

-

9

39.5

1

45.0

4

43

15.0

7

38.5

25

For the direction of the Line

9h 41m 46s

49 47.5

19h 59m 27.5s

9h 59m 44s

Beta Leonis Equal Altitudes

lOh 17m 41.5s 9 55 52 Right Ascension (Beta Leonis)

3m 52s Clock too fast

lOh 49m 45s 12h 27m 50. 5s 23h 22m 11+sl llh 41m 6s Beta Leonis

51 57 30 14 22 11 > 11 37 5 Right Ascension Ditto

54 21- 32 27 22 12 J 4m Is Clock fast

Now as 101' : 9 M : : 82' : 7"

A little 15
dubious on
account of
a screw not
quite fast.

28h 18m 19s j

18 22 > 14h 09m 10s Arcturus

18 20 ) 14 4 59 Right Ascension

4m 11s Clock fast

82

1765
April
. 25

25

Alpha Lyrae

©

H

0

1—1

26

27

Cloudy

llh 11m 8s-

12h 08m

3.5s

14 31

12

37

18 30

16

42

14h 51m 12s
+ 4 1

+ 0 17

14h 55m 30s = Regulus on the Azimuth by the Clock

16h 17m 24s
+ 41

_ + 25

16h 21m 50s Beta Leonis on the Azimuth by the Clock

18h 33m 12s Alpha Lyrae passed the Meridian by the sector
18h 29m 00s Right Ascension
4m 12s Clock fast

12 R 38" O' 57.5"

13 43.5

1° 09' 2.5"

118

23h 27m 08s+

27 08 llh 43m 34s Beta Leonis

27 12. 5 11 37 5 * Right Aseension

6 29 = Clock fast

For the offsets from our line to the first Station, where the greatest error was by the Sector = 43 yards
First for the offsets corresponding to the circle BCW
W, the point set out from 15 miles South of Philadelphia

WS, the Arch run = WB (infinitely near) = WS = 12.312 Miles = 10' 50" Hence in the Right
Angled Spherical Triangle PDW = DBP, we have PW = Complement of latitude = 50° 16' 40"00 and
DW = 5' 25", hence DP = 50° 16' 39:'784

Then PW - DP = DC = 0"216 » 21.6 feet = the greatest offset. And for the intermediate offsets.

Given DP and Da, Db, Dc, etc. = the Sides in minutes and seconds corresponding to the Miles,

to find the Hypothenuses Pa, Pb, Pc, etc. Each of which being subtracted from PW leaves the offsets,

aw, bo, cq, etc., as by table one. And BS = 43 yards

The offsets in the Triangle WBS are at the Miles as according to Table second.

Table 1
Miles from

Sides Da, Db

Sides Da, Db

> Hence the

PW-Pa, Pb, etc

Table 2
Miles Feet

Table 1 + Table 2 r
the true offset from the

the Point W

from the Middle

in Minutes

Hypotenuse

Equal the offsets

from

line we

ran, viz. WS

in Miles

and Seconds

Pa, Pb, etc.

an.

bo, cq, etc.

W

Miles

Feet Chains

Links

1

5. 844

5'

9"

50°16'39"980

0'

0:'020 » 2.0ft.

1 = 10.5

1

12.5 0

19

2

4. 844

4

17

16 39.902

0

0.098 = 9.8

2 = 21. 0

2

30.8 0

46.5

3

3. 844

3

23

39.859

0

0. 141 = 14. 1

3 = 31. 5

3

45.6 0

69+

4

2. 844

2

30

39.824

0

0. 176 = 17.6

4 = 42

4

59.6 0

90

5

1.844

0

57

39. 824

0

0. 176 = 19

5 = 52. 5

5

72. 1 1

09

6

0. 844

0

44

39.784

0

0.216 = 21.6

6 = 63

6

84.6 1

28

6. 156

Middle

0

00

50 16 39.784

0

0.216 = 21.6

7 = 73.5

7

95. 1 1

44

7

1. 156

1

01

16 39. 784

0

0.216 = 21.6

8 = 84

8

103.6 1

57

8

2. 156

1

54

16 39.824

0

0. 176 = 19.6

9 = 94. 5

9

112.1 1

70

9

3. 156

2

47

16 39. 824

0

0. 176 = 17.6

10 = 105

10

119.1 1

80.$

10

4. 156

3

40

16 39.859

0

0. 141 = 14. 1

11 = 115

11

124.5 1

90

11

5. 156

4

32

16 39.941

0

0.059+= 9.5

12 = 126

12

128.0 1

94

12

6. 156

5

24

16 39.980

0

0.020 = 2.0

12.312=129

12.312

129.0 1

95.5

12.312 6.468

12 miles 25 chains

5

50 16 40. 000

0

0.000 = 0.0

To be laid off to the
Southward

IFig.

119

83

Zenith Distances of Stars at the First Point from the 15 Mile Post South of Philadelphia

Plane of the Sector East

1765

April

Capella

Alpha Lyrae

Alpha Cygni

16

lo 9' 4"0

Mean Day

17

6 °

0 ‘

421’0

9 5.0

4°

43'

17i'7

Capella 19. 5

18

9 5.3

Alpha Lyrae 19. lOh in morning

19

9 6.7

Alpha Cygni 19. 5

20

9 5.5

4

43

13.5

At Paris

21

6

0

41.5

Mean

6 ^

O'

41.8"

1° 9' 573"

40 “

43'

15.6"

Mean Day of

Aberration

-4.2

-16.0

+ 18. 0

(Alpha) Cygni is

Deviation

-9.3

- 8.8

+ 6.0

19. 5 at Paris

Precession

-6.9

+3.3

-16.2

Refraction

+7.0

+ 1.2

+5.5

Mean Z. D. 1 Jan. 1764

6 ®"

0 *

28.4"

1° 8 ' 45.0"

w

43*

28.9"

Plane East

Plane of the Sector West

April

Alpha Lyrae

Capella

Alpha Cygni

21

1 °

9*

2 . 0 "

Mean Day

23

1

8

59.0

(Alpha) Lyrae 24th - 5' 00 ”

24

1

9

0.3

CM

CO

o

o

CO

4°

43'

15.0"

Capella 23d 17h

6 0 44. 5

4

43

19.3

Alpha Cygni 24. 5d

25

1

9

2.5

Mean

lo

9'

0.95"

60 0» 46.35"

4^

43*

17.2"

-15.34

-3.7

+ 17.9

- 8.8

-9.3

+ 6.0

+3.3

-6.9

-16.3

+ 1.2

+7.0

+5.5

Mean Z. D. 1 Jan. 1764

W

8 '

41.3"

6 ° O' 33.5"

W

43*

30.3"

Plane West

Ditto, Plane East

1

8

45.0

6 0 28.4

4

43

28.9

True Zenith Distance

1 °"

8 *

43.15"

6 ° O' 30.95"

40

43'

29.6"

At the Post marked West it was

1

8

41.8

6 0 31.8

4

43

31.2

Difference = what

O'

1.35*'

O' 0.85"

O'

1 . 6 "

we are too much

North

North

North

120

Now for the mean of these as follows

/1. 35

\l.35

<1.35

Alpha Lyrae

/l.35

' 1. 35

Alpha Cygni

f 1 . 60

11.60

Capella

(0. 85

10. 85

Mean

1. 29" - 43 yards that we are to the Northward.

Hence the offsets to the Southward as in the leaf before.

1765

April

28 (Sunday)

29 Began to run the Line in the Direction we found last viz. on the 25th Instant

30 Continued Ditto and crossed the main Branch of North East River at 14 Miles 2 Chains.
Sent Expresses to the Commissioners to acquaint them we would be at the River
Susquehanna in 12 days.

84

1765

May

1

2

3

4

5

6

7

8

10

11

12

13

14

15

17

18

19

Continued the Line
Rain

Continued the Line
Continued ditto
(Sunday)

Continued Ditto
Continued Ditto

Continued Ditto and crossed the River Actarara at 20 Miles 61 Chains.

Continued the Line and crossed Acterara at 20 Miles 71 Chains
Crossed Ditto a third time at 21 Miles and 25 Chains

Note at each of these times the River ran nearly at Right Angles with the Line;
its breadth was about 50 yards.

Continued Ditto

Continued Ditto and crossed Coniwingo Creek at 23 Miles 67 Chains

At 26 Miles 3 Chains 93 Links Reached the East Side of the River Susquehannah.

Crossed the River nearly at Right Angles

(Sunday) Set up the Sector in our direction at the distance of 25 Miles and 75 Chains
from the point where we began; and made the following observations:

Plane East

Star Name

Nearest Point

Revolutions and

on the Sector

Seconds on the

Micrometer

0

i

R

it

Alpha Lyrae

1

10-

15

13.2

14

8.2

Delta Cygni

4

50+

13

0.5

12

32.0

Gamma Cygni

0

15-

7

33.0

5

0.3

Delta Cygni

4

50+

1

47.0

1

28.5

Gamma Cygni

0

15-

7

23.5

4

45.3

Alpha Cygni

4

45-

1

47.5

3

46.3

Cloudy

Capella

6

00+

9

14.3

8

27.3

Alpha Lyrae

1

10-

10

6.0

9

2.0

Delta Cygni

4

50+

8

6.3

7

40.5

Gamma Cygni

0

15-

10

4.0

Cloudy

Cloudy.

7

24.5

Continued our direction over

the River Susquehanna

Capella

6

00+

6

35

5

49

Alpha Lyrae

1

10-

7

17

6

11

Delta Cygni

4

50+

6

43-

6

22+

Alpha Cygni

4

45-

6

8

20+

19

(Sunday) Cape 11a

6

00+

6

37.5

6

2-

Alpha Lyrae

1

10-

3

39. 5

2

32+

Delta Cygni

4

50+

8

42+

8

22

Difference

i M

0 57.0

Apparent
Zenith
Distance
o »

1 09

03.0

0

20.5

4

50

20.5

2

16.7

0

12

43.3

0

18.5

4

50

18. 5

2

14.2

0

12

45.8

1

42. 8

4

43

17.2

0

39. 0

6

00

39.0

0

56.0

1

09

04.0

0

17.8

4

50

17.8

2

15.5

0

12

44.5

0

38.0

6

00

38.0

0

* 58.0

1

09

2.0

0

20.4

4

50

20.4

1

42.7

4

43

17.3

0

35.8

6

00

35.8

0

59.2

1

09

00.8

0

20.3

4

50

20.3

121

122

123

85

1765

May

19

Star Name

Nearest Point

Revolutions and

Difference

Apparent

on the Sector

Seconds on the

Zenith

Micrometer

Distance

o

i

R

it

l tr

t H

(Sunday) Gamma Cygni

0

15-

9

10

2 16.0

0

12 44.0

6

30

Alpha Cygni

4

45-

6

41

1 43.7

4

43

8

41-

For a Direction Westward when AB

As Tang. PB 50° 16' 40" =

: Had

: : Tang. AL = LB 10' 00 M =

Cosine Angle LBP 89° 51' 41" =
And
As Rad
Sine
Sine
Sine

: 20' of an arch of a Great Circle
(log)

10.0804662

10 .

7.4637273

7.3832611

50°

89

50

50

16'

51

16

16

10 .

9.8860155

9.9999987

9.8860142

42" PB

41 LBP

41. 26= PL

42. 00- PR

LR - 24.68 yards = the greatest offset, this being

00' 0.74"

V V, ^ - --- J «** gi caiciSl unoci, LHJ.B oe

so great, will throw it out of the Visto too much; therefore shall proceed to
find a new direction on the former arch AB - 10', thus

Right Ascension of Star

On the West Azimuth

9h

55m

52s

14h

51m 12s

Regulus

11

37

5

16

17

24

Beta Leonis

12

43

38

Epsilon Ursae Mai oris: Alioth

14

4

59

18

18

56

Arcturus

Time by the clock

12h

28m

19s

35

27

13h

05m

53s

25h

41m

20s

12h

50m

42s Equal altitudes of Epsilon

Ursae Majoris: Alioth

13m

08s

25h

41m

27s

12h

43m

38s = Right Ascension of Alioth

7m

04s Clock too fast

13h

51m

54s-

14h

19m

42s

28h

24m

04s

56m

44s

14h

27m

26.5s 28h

24m

10.5s

14h

12m

05s Arcturus

14h

4m

22s

14h

32m

22s

28h

24m

16s

14h

04m

59s = Right Ascension

07m

06 s Clock too fast

14h

58m

19s

Regulus

Hence at

16h

24m

34s

Beta Leonis

Will be on the Western Azimuth of 89° 55' 51"

18h

26m

11s

Arcturus

20

21

At these times we placed three marks at the distance (across the River) of 76 chains 60 links
They differ (that is from the Northernmost to the Southernmost) Seventeen inches.

Turned the Sector, Plane West

Cloudy

Alpha Lyrae 1°

Delta Cygni 4

Gamma Cygni 0
Alpha Cygni 4

10'-

7

14+

8

24

50+

8

36

9

6

15-

8

49. 5

11

33-

45-

10

8

9-

1*

1.7"

lo

8’

0

22. 0

4

50

2

19.2

0

1

43.3

4

43

58.3"

16.7

Figure

124

86

1765

May

22

23

25

26

27

Star Name

Nearest Point
on the Sector

Capella

o

6

i

0+

Alpha Lyrae

1

10-

Delta Cygni

4

50+

Gamma Cygni

0

15-

Alpha Cygni

4

45-

Capella

6

00+

Alpha Lyrae

1

10-

Delta Cygni

4

50

Gamma Cygni

0

15-

Alpha Cygni

4

45-

Capella

6

00+

Alpha Lyrae

1

10-

Delta Cygni

4

50+

Gamma Cygni

0

15-

Alpha Cygni

4

45-

Capella

6

00+

(Sunday) Capella

6

00+

Revolutions and

Difference

Apparent

Seconds on the

Zenith

Micrometer

Distance

R

ii

i

II

o

i

8

33

0

40.0

6

00

9

21

7

45+

1

2.7

1

08

9

4

10

30

0

22.5

4

50

11

0.5

9

25

2

19.7

0

12

12

9-

13

32

1

42.5

4

43

11

33.5

6

41+

0

34. 0

6

00

7

23+

6

32

1

3.5

1

08

7

43.5

6

38+

0

22.0

4

50

7

8+

6

8

2

21.0

0

12

8

45

9

22-

1

41.2

4

43

7

24.5

5

48.5

0

39.2

6

00

6

36-

7

10

1

4.0

1

08

8

22

9

42

0

23.0

4

50

10

13

10

25.5

2

21.0

0

12

13

10.5

17

3

1

41.0

4

43

15

6

9

14.5

0

39.0

6

00

10

1.5

13

19.5

0

35. 8

6

00

14 3+

Computing our observations

Computing our observations. The Result whereof as follows

May the 25th in the Evening a storm of Thunder and Lightning: about sun set I was
returning from the other Side of the River, and at the distance of about 1. 5 Mile the
Lightning fell in perpendicular streaks, (about a foot in breadth to appearance) from
the cloud to the ground. This was the first Lightning I ever saw in streaks continued
without the least break through the whole, all the way from the Cloud to the Horizon.

40. 0 very hazy
57.3

22.5
40. 3

34. 0 very dubious

56.5
22. 0
39.0
18.8

i:

39.2

56.0

23.0

39.0

19.0

39.0

35.8

126

1765

May

(Sun.) 12
13
15
18

19 _

Mean 17 1/3

Aberration

Deviation

Precession

Refrac tion

Mean Z. D.

Plane East

Plane of the Sector East

C apella

May

Alpha

Lyrae

o 1

rr

o

r

n

12

1

09

3.0

6 00

39.0

15

1

09

4.0

00

38.0

18

09

2.0

GO

35.0

19

09

0.8

6 00

37.6

16

1

09

2.45

-0.7

-10. 96

-9. 29

-8. 7

-7.26

+3.45

+ 7.0

+ 1.2

6 00 27.35 1 08 47.44

May Delta Cygni May Gamma Cygni
o'" o'"

12 4 50 20.5* 12 0 12 43.3

13 50 18.5 13 12 45.8

15 50 17.8 15 12 44.5

18 50 20.4

19 _ 50 20. 3 19 _ 12 44. 0

15.4 4 50 19.5 14.75 0 12 44.4

+14.6 -14.8

+7.39 -6.46

-11.33 +15.24

_+5JS_ +0.2

4 50 35.76 0 12 38.58

May Alpha Cygni

~ I "

o

i

n

13 4

43

17.2

18

43

17.3

19

43

16.3

16.67 4

43

16. 9
+ 15. 85

+5. 86
-17.05
+5.5

4 43 27.06

87

Plane of the Sector West

1765 Capella

May o 1 "

21
22

23

24 6 00 39.2

25 _6 00 39. 0

(Mean) 24. 5

Aberration

Deviation

Precession

Refraction

6

00

39. 1
+0.27
- 9. 29
-7.37
+ 7.0

22.5 1

08

57.0

-9.4

-8.7

+3.5

+1.2

22.5 4

50

22.4
+13.14
+7.39
-11.5
+5.6

22.5 0

12

39.8

-13.52

-6.46

+15.45

+0.2

22.5 4

43

18. 0
+ 14.9
+5. 86
-17.3
+5. 5

Mean Z , D.
Plane West

6

00

29. 71

1

08

43.6

4

50

37.03

0

12

35.47

4

43

26.96

Plane East

6

00

27.35

1

08

47.44

4

50

35.76

0

12

38.58

4

43

27. 06

i rue Zj. u.

1st Jan. 1764 6

Ditto at the Post

00

28. 53

1

08

45.5

4

50

36,4

0

12

37.02

4

43

27.01

Marked West

6

00

31.8

1

08

41.8

4

50

40.4

0

12

33.0

4

43

31. 2

iXLiierence wnat we
are too much North

0

3. 27
3.7

0

3.7

0

4.0

0

4. 02

0

4. 19

j . i

4. 0
4.02
4. 19

3. 836 * 5 chains 80 links from hence the offsets to our last station from

May

Alpha Lyrae

o

i

Tt

21

1

08

58.3

22

1

08

57.3

23

08

56.5

24

08

56.0

May Delta Cygni

o

i

II

21

4

50

22.0

22

4

50

22.5

23

50

22.0

24

50

23.0

May Gamma Cygni

o '

m

21

0 12

40.8

22

12

40.3

23

12

39.0

24

12

39.0

May

Alpha Cygni

o *

n

21

4 43

16. 7

22

43

17.5

23

43

18. 8

24

43

19.0

(Undated)

From the Line we have run ST = 13 miles 50 chains will be
found to consist of three parts, viz. 1st the circular part
COB = Table 1 CD - SB = a constant quantity
= 43 yards = Table 2, and the Triangle DTS when DT =

(5. 80 chains - DC = BS = 43 yards) 3. 85 chains.

= Table 3. The Sum of these three Tables are the
offsets to the Southward.

Table 1

Table 2

Miles from

Offsets for

Constant

the post W

the Circle

where we began

+

+

Feet

Feet

At S 12.312

0.0

129

13

7. 0

129

14

16. 1

129

15

20.0

129

16

23.6

129

17

25.0

129

18

25.0

129

19

27.5

129

20

27.5

129

21

25.6

129

22

23.6

129

23

19.7

129

24

16. 1

129

25

7.9

129

25 miles 75. 5 chains 0. 0

129

Table 3

Triangle

Sum = True offsets
to the Southward

+

Feet

Feet

Chains

Links

00. 0

129

1

95

13.0

149

2

26

31.5

176.5 =

2

67. 5

50.0

199

3

01.5

69.0

221.5 =

3

36

87.5

241.5 =

3

66

106

260

3

94

125

281.5 =

4

26.5

144

300.5 =

4

55

163

317.5 =

4

81

182

335

5

08

201

350

5

30

219

364

5

51

237

374

5

66

254

383

5

80

Figure

128

88

(Undated)

For the Breadth of the River Susquehannah

A, a Mark on the East Side of
the River 2. 50 chains.

B, a Mark on the West Side 1.10 chains
BC a Base on the West Side - 13. 82 chains
Angles measured as by Figure

dog)

As Sine 9° 53' = 9.2346249

: CB 13.82 = 1, 1405080

: : Sine 62° 17' = 9.9470700

: AB 71. 28 chains = 1. 8529531

Subtract 3. 60 - the distance of the Mark from the River
Rest 67. 68 = Breadth of the River

Miles

Chains

Links

26

1

43

from the Point where we began to the

71

28

Mark on the West Side

26

72

71 *

Distance of the Mark on the West Side, where the chain
Carriers are to begin again.

N, B. Angles measured with a Hadley 1 a Quadrant of 18 inches Radius

1765

May

26

27

n: b.

(Sunday)

Time by the Clock

At 15h 41m 11. 5s by the Clock Alpha Leonis Emerged from the Moon

18 43 53 Alpha Lyrae passed the Meridian by the Sector. R. A, 18h 29m Is

18 43 53
14m 52s

20 48 15 Alpha Cygni Ditto. Right Ascension 20h 33m 27s

48 15

14m 48s

3h 47m 6s 5h 10m 53s\Equal Altitudes Sun's Limbs

49

6

13

20

blence the Sun's center crossed the Meridian by

51

19

15

30

jthe clock at

4h

34m 4. 3s

52

34

16

51 1

Sun's Right Ascension

4h

18m 39 s

54

51

Mid.

i

i

15m 25. 3s Clock fast

3 57

17

5 21

2'

)

5h 14m31s Capella passed Meridian by the Sector R. A. 4h 59m 22s

5 14 31_

15m 9s

Clouds prevented observing the Immersion of the Star but the
Emergence from the Moon was observed with Certainty, with
a Reflector that magnified about 70 Times.

The Observations were made in the Line on the East Side of the River
Susquehannah 1. 5 miles to the South of Peach Bottom Ferry, about
20 miles North of the Head of Chesapeake Bay and 57 miles
West from Philadelphia,

28 Packing up the Instruments, etc.

29 Set out on our return to lay off the offsets; and reached the 20 Mile Post

30 Set off the offsets to the 15 Mile Post.

31 Continued Ditto to the 4 Mile Post

June

1 At the Tangent Point and found a direction for Running a North Line by the

Pole Star and Alioth. Proved the First Meridian by four other stars and found it very good.

2 (Sunday)

Figure

129

130

89

00 oO

1765

June

3 Proceeded to run the North Line

Sent Expresses to Annapolis and Philadelphia to acquaint the Commissioners
we should finish the Line between the Tangent Point and the Parallel this week.

Continued Ditto and Measured the Angle formed by the Radius from Newcastle
and the North Line, and found it = 86° 3 2 1

Hence the offsets at Right angles to the Westward from the Meridian for
the Boundaries of Newcastle County as follows:

Distances from Offsets

the Tangent Point

Chains Links Chains Links

0 00 0 00

8 05 0 46

18 05 0 92

28 05 1 28.5

1 54.5

48 05 1 70.5

58 05 1 75.5 Middle or greatest offset

68 05 1 70.5

78 05 1 54.5

QD 05 1 28. 5

n* 0 92

0 46

0 00 That is, 1 mile 36 chains 10 links = the distance

in the Circle on a due North Course from the
Tangent Point. 131

To find the Meridian at the Tangent Point

Pole Star

0

u°

15’

21“ aberration accounted for

Alioth

6

10°

54’

29"

20'

52" = lm 23. 5s that Epsilon Ursae Majoris will

be on the Meridian (earlier), than the Pole Star, therefore this time must elapse, or nearly,
before the Pole Star is on the Meridian.

R. A.

in Motion

R. A.

Star in Time

13h

12 m

52s

Spica

14

04

59

Arcturus \

12°

57'

18”

14

51

49

Beta Ursae Minoris \

231

11

27

15

24

46

Alpha Coronae Borealis \

243

46

2

16

15

4

Antares ^Sjune

21

18

51

17

25

15

Beta Draconis /

27

47

24

17

51

10

Gamma Draconis /

277

14

56

18

29

00

Alpha Lyrae /

294

50

1

19

39

20

Alpha Aquilae /

308

21

40

20

33

27

Alpha Cygni /

19

37

39

Delt a Cygni the 1st of September

4

59

24

Capella June 1st

A mark being placed North by the Pole Star and Alioth, the
Instrument was turned to the South; and the Passage of Spica over

the Meridian by the Clock at

15h

33m

14. 5s

13h

12m

52 s

= Right Ascension Spica

2h

20m

22 s

Clock fast by Spica

15h

41m

1.5s

17h

05m

17 s

32h

50m

50 s )

|

43

13

7

37

50

50 1

\ 16h

25m

25s Equal alt. Arct.

45

33

9

47

50

48.5

14h

4m

59s Right Ascension

2h

20m

26s Clock fast, Arct,

17h

17m

4. 5s

18h

08m

31s

35h

30m

31 s>

)

19

22

11

8.5

30

31 |

1

17h

i

45m

15. 5s Equal alt. of
Alpha Coronae Borealis

00

13

26

30

30.5 ,

J 15

24

46 Right Ascension

2h

20m

29. 5s Clock fast by

Alpha Coronae Borealis

90

From foenoe at

/l«h

35m

36s

Antares will pass the Meridian

by the Clock

119

45

50

Beta Draconis Ditto. (A Dubious Observation was made on this star)

)20

11

47

Gamma Draconis Ditto

122

0

1

Alpha Aquilae Ditto

At these times the stars were set to the Middle Wire of the
Transit Instrument and then run down to the Horizon and at the distance
■ of about ISO Yards the extremes differed only two Inches from the

Mark placed by the Pole Star and Alioth. 132

(Undated)

The Work as follows for finding the Offsets for the Boundaries of Newcastle County

(A Column of logarithmic calculations not transcribed. )

Here let NA (be) the Radius from Newcastle

APB the Meridian Northing
Angle NAB = 86° 32* Measured: Then
Angle ANP = 3° 28’ and by Trigonometry

As Rad. 10. 0000000

:Hyp AN 12 miles = 96, 000 links = 4. 9822712

::Sine ANP = 30 28' = 8.7815244

:AP = PB 5804. 9 = 3.7637956

11609.8 = AB

As Sine 3° 28' = 8.7815244

:AP 5804. 9 Links = 3.7637956

;:Sine 86° 32' = 9.9992046

13.7630002

:PN 95824. 5 = 4.9814758

DN 96000

175. 5 = DP - the greatest offsets

Distance

Offsets

Chains

Links

Chains

Links

8

05

0

46

18

05

0

92

28

05

1

28. 5

38

05

1

54. 5

48

05

1

70.5

58

05

1

75. 5 -

Middle or greatest (offset) DP and according to the property

68

05

1

70.5

of the Circle this point is due West from Newcastle.

78

' 05

1

54. 5

88

05

1

28. 5

98

05

0

92

108

05

0

46

.

116

10

0

00

Miles Chains Links

1 36 10 Figure

the Distance in the Circle on a due North Course. 133

1765

June

4 Set off the offsets, etc. Mr. Enoch Morgan’s

House at 71 chains from the Tangent Point, is 5 chains East of the
Circular Line.

5 Continued the Line to about the 4 Mile Post

91

1765

June

6 Continued Ditto to the Parallel of Latitude 15 Miles South
of the Southernmost point of the city of Philadelphia.

♦ From the Tangent Point to the said Parallel on a due
North course is 5 miles one chain and 50 links horizontal
measure.

♦On December 10th and 11th, 1766 Messrs. Darby and Cope remeasured
this line and found it 5 Miles two chains and 43 Links.

At 2 Miles 78 Chains from the Tangent Point Mr. Golespier
Meeting - House 10 Chains to the Eastward of the North Line.

At 3 Miles two Chains from Ditto crossed the Road leading
from Newark to Nottingham.

At 3 Miles 3 Chains, Mr. John Ranking House to
the West of the Line 50 Links.

At 3 Miles 45 Chains crossed Christianna Creek.

At 4 Miles 68 Chains crossed the road leading from
Newark to the Cross Roads.

The Meridian from the Tangent Point crossed the Parallel
at 2 Miles 79 Chains 27 Links, from the Point
where we began to run the Parallel.

7 Note : At the point of intersection of the Parallel of Latitude
and the Meridian from the Tangent Point, we placed a Post
marked W on the West Side and N on the North Side.

It stands in a meadow belonging to Captain John Singleton, 13 chains
50 Links to the North of the Road leading from Newark to the
Cross Roads and 25 chains 73 Links to the East of Little
Christianna Creek, also it is 49 chains 73 links to the East
of Mr. Rice Price's House.

9 Sunday\

►Waiting for the Commissioners

16 Sunday

17 The Commissioners of both Provinces met at
Christianna Bridge in Newcastle County.

18 Seven Stones were set as Marks for Boundaries,
viz. one at the Tangent Point, four in the Periphery
of the circle around Newcastle, one between the
Intersection of the Periphery with the North Line and the
Intersection of the North Line and Parallel; and one at
the Intersection of the North Line with the Parallel

of Latitude 15 Miles South of the Southernmost Point of
the City of Philadelphia.

The Gentlemen Commissioners present.

Received our Instructions to continue the Parallel
of Latitude (in the same manner we have run it to the
River Susquehannah) as far as the country is
inhabited, etc.

19 Prepared to return to the River Susquehannah.

20 Wrote to the Honorable Proprietors of Maryland
and Pennsylvania.

21 Set out for the River.

22 Reached Ditto at Peach Bottom Ferry.

10

11

12

13

14

15

134

135

92

1765

June

23 Sunday

24 In order to fall into the true Latitude, at the
distance of 11. 37 Miles from a point on the East Side
of the River Susquehannah, we changed the direction
found by the stars on the 19th of May, thus,

as 11. 37 miles : 580 links, the whole error :; 1 mile 14 chains 92 links = Radius we measured:

68. 5 links. This 68. 5 Links we laid off at Right Angles to

the Southward of the direction found by the stars and there placed

a mark, and in the direction of this, and the Mark

on the East Side of the River (where the Radius 1 mile 14 chains 92 links
began) we proceeded to Rim the Line.

Continued the Line.

25 Rain

26 Continued the Line. At 28 Miles from

the Post Marked West Mr. Daniel Camel 1 s House
4 Chains to the South of the Line.

At 28 Miles 69 Chains crossed the Road leading from
Rock Run to York; at this Road a School House one
chain to the Southward.

27 Continued the Line. At 30 Miles 42 Chains Mr. James
McKenley' s House 3 Chains to the North.

28 Continued the Line.

29 Continued the Line. At 31 Miles 13 Chains Mr. James
Reed's House, one chain to the North.

30 Sunday

July ,

1 Continued the Line.

2 Continued the Line. At 34 Miles 77 Chains Mr. Thomas Matson's House five Links to the North.

3 Continued the Line. At 37 Miles 17 Chains 98 Links we supposed to be in the true Parallel and

changed our direction to the Northward as follows.

Here PD, PA and PB = complement of Latitude of the true parallel.

SP = Complement of Latitude at the Sector on the East Side of Susquehannah - 50° 16' 36" 17
SC the direction from thence by the stars

SN = 1 mile 14 chains 92 Links - a Radius measured which gives NM = 60. 5 Links. See page before.
Hence the angle NSM thus

(log)

as 9492 Links = NS = 3. 9773577

: Rad = 10.

:: 60. 5 NM = 1. 7817554

: Tang NSM 0 o 21'55 n = “ 7.8043977

Angle PSC 89°55'51 n See minutes following April 4th.

Angle PSA 90°17 , 46 n Now in this oblique angled Spherical Triangle.

PSA there is given this angle and SP * 50° 16’ 361'17, also AP = 50° 16' 40"

Hence the angle SAP = 89° 33’ 58"

and the angle BAC “ 89° 55' 51"

Sum * 179 u 29’ 49"

Subtract from 180° 00' 00”

Rest - 0° 30' if" = angle dAo which we must lay

off to the North at Right Angles to the Course SA to give the course
AB to be again in the true Parallel at B, when we have run

AB = (10' on the arch of a great circle) - 11. 37 Miles. In order to lay off this angle let Ad
be measured 40 chains. Then

(log)

as Rad 10.

: 40 Chains 1.6020600

:: Sine 30' 11" dAo 7.9432479

: do, 35.1 Links 9.5453079 At A the ground not admitting Links Links

to measure Ad = 40 Chains, but only 24 Chains 71 Links. Then as 40:35.1::24. 71:21. 7
= what we laid off at Right Angles from SAd, which gave the line AoB Figure

which we measured as follows.

93

1765

July

4 Continued the Line.

5 Continued the Line. At 43 Miles Mr. Andrew Boyd's Bouse 13 Chains North.

6 Continued the Line.

7 Sunday

8 Continued the Line. At 44 Miles 00 Chains Mr. Henry Wood's House 3 Chains North.

Continued the Line. At 46 Miles 40 Chains crossed the main Branch of Deer Creek.

Continued the Line.

Waggons brought the Instruments.

Set up the Sector in our Direction at the Distance of 48 Miles 64 Chains 5 Links from the Post marked
West, in Mr. Bryan's field, and made the following observations. I3g

Plane of the Sector East

9

10

11

12

15

16

Star Name

Nearest Print

Revolutions and

Difference

Apparent

on the Sector

Seconds on the

Zenith

Micrometer

Distance

o

i

R

ri

t

rr

o

t

it

Alpha Lyrae

1

10-

4

11-

1

20.2

1

08

39. 8

2

34.5

Gamma Cygni

0

15-

4

19

2

37.0

0

12

23. 0

1

18

Alpha Cygni

4

45-

6

37

1

22.7

4

43

37. 3

Capella

6

00+

11

10

10

21.5

Alpha Lyrae

1

10-

9

42+

1

19.6

1

8

40.4

8

15-

Capella

6

00+

7

45.5

0

33. 0

6

0

33. 0*

7

12.5

Alpha Lyrae

1

10-

5

51

1

20.3

1

a

39.7

4

23-

Gamma Cygni

0

15-

6

6-

3

2.5

Capella

6

00+

4

43

0

33. 5

6

0

33.5

4

9.5

Alpha Lyrae

1

10-

9

10

1

20. 0

1

a

40.0

7

34

Delta Cygni

4

50+

9

1

0

42.3

4

50

42.3

8

11-

Gamma Cygni

0

15-

7

50+

2

38.3

0

12

21.7

4

48

Alpha Cygni

4

45-

5

23. 5

1

20.2

4

43

39.8

7

00-

Alpha Lyrae

10-

9

28.5

1

21.0

1

08

39.0

7

51. 5

Delta Cygni

4

50+

9

6.5

0

43.0

4

50

43.0

8

15.5

Gamma Cygni

0

15-

9

29. 5

2

37.5

0

12

22. 5

6

28

Alpha Cygni

4

45-

7

23.5

1

21.5

4

43

38.5

139

94

1765

July

17

18

19

20

Turned the Instrument

Plane of the Sector West

Star Name

Nearest Point

Revolutions and

Difference

Apparent

on the Sector

Seconds on the

Zenith

Micrometer

Distance

0

i

R

n

II

o

i

it

Alpha Lyrae

1

10-

8

11.5

1

23.5

1

08

36.5

9

43

Delta Cygni

4

50+

10

00

0

46.3

4

50

10

46+

Gamma Cygni

0

15-

10

14

2

38.3

0

12

13

16+

Alpha Cygni

4

45-

12

30

1

21. 5

4

43

11

0.5

Capella

6

00+

9

18.5

0

37.0

6

0

10

3.5

Alpha Lyrae

1

10-

10

5-

1

21.8

1

08

11

34. 5

Delta Cygni

4

50+

11

50

0

45.7

4

50

45.7

12

44-

Gamma Cygni

0

15-

11

46+

2

39.7

0

12

14

50

Alpha Cygni

4

45-

14

21+

1

19. 3

4

43

12

46

Capella

6

0+

5

48+

0

38,4

6

00

6

35-

Alpha Lyrae

1

10-

6

2

1

23. 5

1

08

7

33.5

Delta Cygni

4

50+

6

36

0

46. 3

4

50

7

30+

Gamma Cygni

0

15-

7

6

2

39.7

0

12

10

10-

Alpha Cygni

4

45-

10

9

1

19.0

4

43

41.0

8

34

Capella

6

0+

7

41

0

35.0

6

00

35.0

8

24

Alpha Lyrae

1

10-

10

34

1

22.0

08

38.0

12

12

Delt a Cygni

4

50+

14

30

0

45.5

4

50

45.5

15

23.5

Gamma Cygni

0

15-

15

21-

2

42.0

0

18

27-

Alpha Cygni

4

45-

17

7+

1

18.8

4

15

32.5

Capella

6

0+

12

7.5

0

36. 0

6

12

43. 5

95

1765

July

18

19

20

For the Direction at the Third Point from Mr. Bryan's near the
Road Leading from York Town to Baltimore
Right Ascension

Arc Time

277° 44' 57 n 18h 29m 00s Alpha Lyrae

308° 21' 40" 20h 33m 27s Alpha Cygni

Right ascension Mid-Heaven 23h 39m 19s Eta Pleiades (Tauri) on the Azimuth in the East

Right ascension Ditto 23h 43m 46s Aldebaran in Ditto

18h

20m

16s)

21m

22s >

(Indistinct)

Equal Altitudes: Alpha Lyrae

22m

31s)

19h

14m

11. 5s

1

17m

04s

f

Ditto. Delta Cy gni

At

18h

39m

22s

Alpha Lyrae passed the Meridian by the Sector

5h

10m

09s

Capella Ditto

At

( 18h

40m

42s

Alpha Lyrae)

t 20h

45m

06s

Alpha Cygni ^Passed the Meridian by the Sector

(Indistinct)

Capella )

18h

03m

58s

19h

15m

30s+

27h 21m 38s

5m

01s+

16m

37s-

18h 40m 49s Equal Altitudes of Alpha Lyrae

6m

07s

17m

40s

R. A. = 18h 29m 00s

11m 49s Clock fast

2 Oh

04m

59s

21h

23m

08s

06m

17s

24m

29s

41h 30m 16s 20h 45m 23s Ditto Alpha Cygni

07m

38s

25m

47s

R. A. 2Oh 33m 27s

11m 56s Clock fast

Hence by the Cloc

k at

22h 05m 4s Alpha Arietis Will be on the Azimuth

23h 51m 26s Eta Pleiades (Tauri) of 90° 04' 09" in

23h 55m 53 s Aldebaran the East

When Alpha \rietis passed the

(Calculated) Azimuth we placed a Mark.

Cloudy when tt other stars passed.

141

21 Sun. Time by the Wa h
18h (13m) 22

14m 25s

15m 32s

Alpha Lyrae
Alpha Cygni
20h 07m 41s

8m 59s
10m 22s

For the Direction

19h

08m

45.5s

37h 24m 17.5s

09m

53s

24m 18s 18h 42m 09s Equal altitudes. Alpha Lyrae

10m

56s

24m 18s 18h 29m 00s

13m 09s Clock fast

18h

42m

00s

Passed the Meridian by the Sector

2 Oh

46m

25.5s

21h

23m

0. 5s

41h 33m 22.5s

24m

23s

33m 22s 20h 46m 41. 5s Equal altitudes of Alpha

25m

42s

33m 23s Cygni

2Oh 33m 27s = Right Ascension of Star

13m 14. 5s Clock fast

as 124'

: 5L'5

80' : 3”

21h

53m

03s

+

13m

14.5s

+

00m

03s

22h

06m

20.5s

Alpha Arietis will be on the Azimuth

23h

39m

19s

+

13m

14s

+

0

08s

Eta Pleiades (Tauri) Ditto

23h

52m

41. 5s

23h

43m

46s

+

13m

16.5s

+

0m

08s

23h

57m

8. 5s

Aldebaran will be on Ditto

58m

28s

Aldebaran passed the vertical wire

At

1765

July

21 When Alpha Arietis and Aldebaran passed the said Azimuth we placed two
marks. The extremes of the differences between these and that placed last
night was Six Inches at the distance from the Transit Instrument

19. 31 Chains.

We compared the Line we ran in last; with this new direction found by the stars
and at the above distance 19 chains 31 links it agreed within two inches.

22 Computing our observations as follows.

Plane East

Alpha Lyrae Delta Cygni Gamma Cygni Alpha Cygni Capella

o t '» O t " O l ii O I II O t

12

13

14

15

16

1

08

08

39. 8
40.4
39.7

40. 0
39.0

15

16

4

4

50

50

42.3

43,. 0

12

15

16

0

0

0

12

12

12

23.0

21.7

22.5

12

15

16

4

4

4

43

43

43

37.3

39. 8
38.5

13

14

6

00

00

33.3

33.5

Mean 14. 5

1

08

39.78

16

4

50

42.65

14.2

0

12

22.40

14.2

4

43

38.53

14,9

6

33.25

Aberration

+5.36

- 1.87

- 0.21

+ 1.79

+ 6.23

Deviation

-8. 25

+ 7.11

- 6.08

+ 5.48

- 9.20

Precession

+ 3.87

-12.72

+17.08

-19. 12

- 8.10

Ref raction

+1.20

+ 5.60

+ 0.20

+ 5.50

+ 7.00

Mean Zemtn

Distance

1

08

41.66

4

50

40.77

0

12

33.39

4

43

32. 18

6

00

29. 18

Plane West

17

1

08

36. 5

17

4

50

46.3

17

0

12

21.7

17

4

43

38.5

17

6

00

37.0

18

08

38. 2

18

45.7

18

20.3

18

40. 7

18

38.4

19

36. 5

19

46.3

19

20.3

19

41. 0

19

35. 0

20

38.0

20

45.5

20

18.0

20

41. 2

20

36.0

Mean 19. 0

1

08

37.30

19.0

4

50

45.95

19. 0

0

12

20.07

19.0

4

43

40.35

19.0

6

00

36,60

Aberration

+ 6.60

- 2.78

+ 0.99

+ a 54

+ 6.63

Deviation

- 8.55

+ 7. 11

- 6.08

+ 5.48

- 9.20

Precession

+ 3.89

-12.79

+ 17.21

-19.26

- 8. 17

Refraction

+ 1.20

+ 5.60

+ 0.20

+ 5. 50

+ 7.00

1

08

40.44

4

50

43.09

0

12

32.39

4

43

32.61

6

00

32. 86

Plane East

1

08

41.66

4

50

40.77

0

12

33.39

4

43

32. 18

6

00

29. 18

True Zen. Dist,

1st Jan 1764

1

08

41.05

4

50

41.93

0

12

32. 89

4

43

32.39

6

00

31. 02

Ditto at the Post

Marked West 1

08

41.80

4

50

40.40

0

12

33.00

4

43

31.20

6

00

31. 80

Difference what

we are too much

0.75

1.53

00. 11

1. 19

0.78

South

South

South

South

North

+0.75
+ 1. 53
+ 0 . 11
+ 1. 19
3.58
-0.78

5 72 .80

0. 56 second = 56 feet = 85 links, that we are to the
South of the true parallel from the mean of all the stars,

97

(Undated) Hence the offsets at every mile from the River Susquehannah as follows

Here C d D the true parallel
D' the Sector at the River
D Ditto at the first station from the River
D'C = 5. 88 Chains North of Parallel
DF = 0. 85 South of Ditto; then

dE = 0. 38 = Error South (at the Middle nearly) where we changed
the direction; found by proportion, etc.

Then the offsets from the direction DE and EF at every mile Post, will consist
of two parts, thus,

1765

Miles from

the Post Marked

West

Offsets for
the arch dc
+

Offsets for the
Triangle dDC
+

Chains

Links

Chains

Links

26

0

1

5

76

27

10

5

20

28

17

4

65

29

22

4

10

30

25

3

56

31

27

3

02

32

27

2

47

33

26

1

92

34

23

1

37

35

H-

00

0

82

36

12

0

27

37

4

0

28

38

6-

0

42

39

14

0

46

40

20

0

50

41

24

0

54

42

27

0

58

43

27

0

62

44

27

0

66

45

24

0

70

46

20

0

74

47

14

0

78

48

6

0

82

48 mi. 64 ch. 05 li.

0

0

85

True offsets
to the Parallel

Chains

Links

5

77

South

5

30

4

82

4

32

3

81

3

29

2

74

2

18

1

60

1

00

0

39

S. At 37.225 miles. Angular Point

0

24

N. (Offset) = 40-2 = 38 Links North

0

36

0

32

0

30

0

30

0

31

0

35

0

39

0

46

0

54

0

64

0

76

Figure

0

85

North 144

July

23 Packing up Instruments; Laid off the Direction, etc., etc,

24 Began to run the Line to be 56/2 feet South of the true Parallel at 10’ West.

At 49 miles 7 chains crossed the lower Road leading from York to Joppa and Baltimore
at 49 miles 67 chains Mr. John Lawson's House 4 chains to the South,

25 Continued the Line

At 50 miles 44 chains crossed the 1st branch of Gunpowder
51 miles 17 chains crossed second Ditto

26 Continued the Line

At 52 miles 18 chains crossed the Main Branch of Ditto

27 Continued the Line

Miles

Chains

( 55

8

Crossed a small Branch of Gunpowder (river)

At

155

68

Crossed another of Ditto

j 56

4

Crossed another of Ditto

\56

35

Crossed another of Ditto

28 Sunday

98

1765

July

29 Continued the Line

At 57 miles 36 chains crossed a Branch of Gunpowder at half
a mile to the North of this is the Source of Codorus.

At

Miles

Chains

(57

66

J 58

58

J58

66

159

3

A Branch of Gunpowder
Mr. Valentine Vant's House 50 links North
Crossed the upper Road from York to Baltimore
A Spring running into Gunpowder (river).

30

31

Continued the Line
At 60 miles 33 chains crossed the last branch of Gunpowder

Supposed to be in
the true Parallel
+ 28 feet North

Continued the Line

Ai

c 60 miles 57 chains

^Changed our direction 8' 18" to the Northwest
18 links < that is to be in the true Parallel 10 1 West =

I 11.37 miles

145

Mites

Chains

(G2

38

Mr. George Rinot' s House 6 Chains to the South of the Line

39

Crossed the 1st branch of Codorus.

/ G2

47

Mr. Elias Hoarish's House 7 Chains South.

) 52

57

Crossed a Road from Baltimore to M'Allistor's Town

3

Mr. Peter Stophel's House 25 Links South

Us

15

A Branch of Codorus

August

1

Continued the Line
Miles

Chains

;63

76

Third and last Branch of Codorus

At \

64

35

Mr. Henry Fight's House 7 Chains South

1

164

60

Mr. Staph el Rinoman's House 2 Chains South

Continued the Line

Miles

Chains

i

[66

00

Crossed the 1st branch of Conewago

At <

66

21

Crossed a 2nd Ditto

1

167

18

Mr. Michael Worth's House 5 Chains South

3 Continued the Line

At 68 miles 28 links crossed a 3rd and last branch of Conewago

4 Sunday

5 Continued the Line

70. 00 (miles) Mr. Henry Hiltibrand's House 6 Chains North
70. 26 (miles) Crossed Piney Run: This runs into Monocacy which
empties into the great River Potowmack
70. 63 Crossed the Road leading from Baltimore to the Temporary Line.

6 Continued the Line

Crossed Piney Run six times in Running 46 Chains
from the last Road.

At 71 (miles) 42 (chains) 62 (links) a Board or Station.

7 Set up the Sector in our direction at the distance

of 71 miles 43 chains 19 links from the Post marked West, in Mr. Bryan's
field and made the following observations.

146

Plane of the Sector East

Star Name

Nearest Point

Revolutions

Difference

Apparent

on the Sector

and Seconds on

Zenith Distance

the

Micrometer

o

i

R

tr

i

it

o

i "

Gamma Cygni

0

15-

8

49

2

36.7

0

12 23.3

5

48+

Alpha Cygni

4

45-

6

42

1

21.5

4

43 38.5

8

19.5

99

1765

August

8 At Noon a great storm of Thunder, Lightning, Hail and

Rain. The Hail intermixed with pieces of ice; one piece of
an irregular form measured one inch and six tenths in Length, one inch
two tenths in breadth and half an inch thick.

Star Name

Nearest Point

Revolutions

Difference

-Apparent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

n

ii

o

M

Cape 11a

6

0+

7

19+

0

26.8

6

00

26.8

6

44. 5

9

Alpha Lyrae

1

10-

8

24+

1

21.6

1

08

38.4

6

47-

Delta Cygni

4

50+

6

29-

0

44.0

4

50

44.0

5

37-

Gamma Cygni

0

15-

7

03

2

40.0

0

12

20.0

3

51

Alpha Cygni

4

45-

4

13

1

18.0

4

43

42.0

5

39

10

Capella

6

00+

9

26

0

28.7

6

00

28.7

8

49+

147

Plane East

11 Sunday

Alpha Lyrae

1

10-

8

22

1

19.7

1

08

40.3

6

46+

Delta Cygni

4

50+

5

33

0

43.0

4

50

43.0

4

42

Gamma Cygni

0

15-

5

2

2

41.0

0

12

19.0

1

49

Alpha Cygni

4

45-

2

17+

1

19.7

4

43

40.3

3

45

Capella

6

0+

7

33+

0

29.3

6

00

29.3

7

4

12 Alpha Lyrae

1

10-

9

15+

1

21.8

1

08

38.2

7

37.5

Gamma Cygni

0

15-

6

42-

2

42.2

0

12

17.8

3

35.5

Alpha Cygni

4

45-

3

39+

1

15.7

4

43

44.3

5

11

13 Turned the Sector

Pla: e West

Alpha Lyrae

1

10-

7

9

1

27,0

1

08

33.0

8

44

14 Alpha Lyrae

10-

9

11.5

1

26.0

08

34.0

0

45.5

Delta Cygni

4

50+

7

12

0

48.0

4

50

48.0

8

8

Gamma Cygni

0

15-

9

25

2

46.0

0

12

14.0

2

35

Alpha Cygni

4

45-

2

27+

1

16.3

4

43

43.7

1

03

Capella

6

0+

6

32-

0

30.3

6

00

30.3

7

10

100

1765
August

15

Star Name

Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Capella

16 Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Capella

17 Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni

18 Sunday

Capella

19 Computing our observations

50+

7

37

8

32

15-

7

48-

11

05+

45-

8

43+

7

18.5

00+

4

31+

5

11

10-

4

43+

6

26. 5

50+

6

44+

7

43

15-

6

05-

9

16-

45-

9

11

7

38

0+

9

45+

10

21.5

10-

7

38

9

20.5

50+

10

31

11

27

15-

10

42

13

51

45-

14

00

12

29

00+

5

28

6

07.5

The results of which see following -

Difference Apparent

Zenith Distance

t

it

o

i

it

1

28.0

1

08

32. 0

0

47.0

4

50

47.0

2

45.6

0

12

14. 4

1

16.8

4

43

43.2

0

31. 7

6

00

31.7

1

27.2

1

08

32.8

0

50. 7

4

50

50. 7

2

47.0

0

12

13.0

17.0

4

43

43.0

0

28.2

6

0

28.2

26.8

1

08

33.2

0

48.0

4

50

48. 0

2

45.0

0

12

15.0

1

15.0

4

43

45. 0

0

31.5

6

00

31.5

149

Plane of the Sector West

Nearest Point
on the Sector

o

1

4

0

4

6

1

4

0

4

6

1

4

0

4

10 -

Revolutions
and Seconds on
the Micrometer
3 20.5

5 4.5

(Undated) NOTE:

We laid off the angle of 8' 18" (recorded) in minutes of 30th of July
thus, suppose AB, a Radius measured = 40 Chains

log

Then as Rad -

to AB 4000 links = 40 Chains =
: : Sine of 8' 18" BAC
: BC = 9. 6575 Links =

10 .

3.6020600

7.3828038

0.9848638

But the ground not admitting of a Mark to be seen 40 Chains

but only 32.82 Chains. Then as 40: 9,657 Links : : 32.82 : 7.9 Links

at the said distance of 32. 82 Chains we laid off at Right Angles 7. 9 Links Figure

and proceeded to run as on the 31st July etc., etc. - 150

101

1765

August

16 For the direction at our Station 71 Miles from the Post Marked West in Mr. Brian's Field.

h

m

s

18

29

00 =

Right ascension Alpha Lyrae

20

33

27 =

Right ascension Alpha Cygni

21

53

03)

1 Alpha Arietis

23

39

i®t =

Right ascension Mid-Heaven >Eta Pleiades (Tauri)

23

43

46;

) Aldebaran

h

m

s

h

m

s

17

56

56.5

19

21

39

37

20

44

57

58.5

22

44

20

42. 5 Equal Altitudes Alpha Lyrae

59

05

23

46

20

42.5

18

40

21.5

29

00

11

21.5 Clock fast ^

18

40

14

Alpha Lyrae > Passed the Meridian

20

44

37

Alpha Cygni ) by the Sector

20

02

04

21

25

08

41

29

52-

3

26

26

31. 5

29

57. 5 Equal Altitudes of Alpha Cygni

4

44

27

47

29

51-

20

44

56

33

27

11m 29s = Clock fast

as

124m

: 7. 5s

80m

. : 5.

5s and as 124m : 7. 5s 190m : 12s

21

53

03

+

11

29

+

0

5.5

22

4

37

Alpha Arietis passes the direction, or Azimuth of 90° 04' 09"

h m s

23

39

19

23 43 46

+

11

29

+ 11 29

+

00

12

+ 00 12

23

51

00

Eta Pleiades (Tauri) Ditto 23 55 27 Aldebaran Ditto

When Aldebaran passed, we placed a mark at the distance of ------ /rom the Instrument.

For

the direction Continued

h

m

s

h

m

s

h

m

s

17

54

37+

19

26

47+

37

23

34+

55

41+

27

52

23

33+

56

47

28

55

23

32+

18

41

47-

18

29

00 Right ascension of Star

12

47- Clock fast

18

41

36

Alpha Lyrae) Passed the Meridian

20

46

01

Alpha Cygni / by the Sector

20

07

22. 5

21

22

40

41

32

44

08

42

24

1.5

32

43. 5

10

04

25

20

32

42. 5

20

46

21.5

20

33

37

12

44.5 Clock fast. As 124m : 7.8s 80m : 5s

21

53

03

+

12

54.5

+

05

22

06

03 =

Alpha Arietis passes the Azimuth

23

52

25.5

Eta Pleiades (Tauri) Ditto

23

43

46

12

54.5

+

0

12

23

56

52. 5 =

Aldebaran Ditto

When these three Stars passed the Azimuth (90° 04* 09" from the North) in the East, the wire
bisected a candle placed at the mark we set last night sq near that it could not be bettered. 152

102

1765

August

Plane East

Alpha Lyrae

Delta Cygni

Gamma Cygni

Alpha Cygni

Cape 11a

O r

m

o t

it

o

•

ii

o t

ti

O | it

8

8

6 00 26.8

9

1 08

38.4

9

4 50

44. 09

9

0

12

20. 0

9

4 43

42.0

10

10

6 00 28.7

11

1 08

40.3

11

4 50

43. 0

11

0

12

19.0

11

4 43

40.3

11

6 00 29.3

12

1 08

38.2

12

0

12

17. 8

12

4 43

44.3

Mean lid lh 1 08 38.97 lOd lOh 4 50 43.5 lid 3h 0 12 18.93 Ild3.5h 4 43 42.20 10dll.5h 6 00 28.27

Aberration

+ 12.24

- 9.24

+ 7.47

- 6.28

+ 7.80

Deviation

- 8.40

+ 6.90

- 5.90

+ 5.30

- 9. 15

Precession

+ 4.06

-13.32

+ 17. 88

-20.04

- 8.51

Refraction

+ 1.20

+ 5. 60

+ 0.20

+ 5.50

+ 7.00

Mean Zen. Dist.

1 08 48.07

4 50 33.44

0 12 38.58

4 43 26.61

6 00 25.41

Hane East

Plane West

August 13 1 08 33.0

14

08

34.0

14

4

50

48.0

14

0

12

14.0

14

4

43

43.7

14

6

00

30.3

15

08

32.0

15

50

47.0

15

12

14.4

15

43

43. 2

15

00

31.7

16

08

32.8

16

50

50.7

16

12

13.0

16

43

43.0

16

00

28.2

17

08

33.2

17

50

48.0

17

12

15.0

17

43

45. 0

18

18

6

00

31. 5

s

Mean

15d 9h

1 08

33.0

15d 22h

4

50

48.43

15d 23h

0

12

14. 10

15d 23h

T

43

43.73

16d 13h

6

00

30.42

Aberration

+13.14

-10.67

+ 8.72

- 7.64

+ 7.94

Deviation

- 8.40

+ 6.90

- 5.90

+ 5.30

- 9.15

Precession

+ 4.09

-13.44

+ 18.03

-20.21

- 8.60

Refraction

+ 1.20

+ 5.60

+ 0.20

+ 5.50

+ 7.00

Mean Zen. Dist.
Plane West

1

08 43.03

4

50

36.82

0

12

35. 15

4

43

26.68

6

00

27.61

Ditto East

1

08 48. 07

4

50

33.44

0

12

38.58

4

43

26.68

6

00

25.41

True Zen. Dist.

1

08 45. 55

4

50

35. 13

0

12

37.06

4

43

26.68

6

00

26. 51

1 Jan. 1764

Ditto at the Post
marked West

1

08 41.80

4

50

40.40

0

12

33.00

4

43

31.20

6

00

31.80

Distance from the

0

00 3.75

00

5. 27

00

4.06

00

4. 52

0

00

5.29

true Parallel

North

North

North

North

North

3" 75
5” 27
4'J 06
4’.' 52
gj 29

ffl 58 = Mean = 6 chains 94 Links that we are to the North of the true Parallel

Hence

153

(Undated)

(Undated)

Hence the offsets at every Mile Post to where the Sector
was set up on the 12th of July as follows.

Here F (is) the Sector at the 48 Miles 64 Chains Station

N Ditto at this Station, that is 71 Miles 43 Chains from the Post marked West.
DF = 0 Chains 85 Links South of the Parallel

HN * 6. 94 North of Ditto

Hence the offsets

Miles from the Post marked West
For the circle

For the Triangle

True offsets

GF and GH

dFD’: dGL and

to the Parallel

Miles Chains Links Chains

Links

the part (Indistinct)
Chains Links

Chains

Links

48 64 5 0

0

0 85N

0

85N

49 0

3

0 78

0

75N

50 0

10

0 43

0

33N

51

18

0 8N

0

10S

52

22

0 26S

0

48S

53

25

0 60.5

0

85.5

54

27

0 95.5

1

22.5

55

27

1 30

1

57

56

25

1 65

1

90

57

21

2 00

2

21

58

15

2 34

2

49

59

10

2 69

2

79

60

3

3 04

3

07

60.71

61

7

3 29

3

3

23 at 60. 71 Miles the Angular
36 Point, the offset = 3, 23

62

14

3 63

3

77

63

20

3 98

4

18

64

24

4 34

4

58

65

26

4 69

4

95

66

27

5 03

5

30

67

26

5 38

5

64

68

23

5 73

5

96

69

19

6 08

6

27

70

13

6 42

6

55

71

5

6 76

6

81

71 43 19

0

6 94

6

94S

Miles

Point/F = 48. 806

F =

48. 806

Error at F 0. 85S

IN = 71.540

G =

60.710 changed at

Ditto at N 6. 94N

Whole length 22.734

then

11.904 = FL

Sum 7.79

Then as 22. 734 : 7. 79 chains ;

:: 11. 904 : 4. 08 chains; and then 4. 08

- 0. 85 (being S)

= 3 chains 23 links = LG - the

distance of the true Parallel (or infinitely near) at the

Point of change. And as FL = 11. 904 we have over run 11. 37 by 0. 534 of a mile
= QL at an angle of 8' 18” (vid ) then as Had: to QL :: Sine 8* 18 1 = LQR; LR = 10 Links
NO which we should have been more North, had we changed at 11. 37 miles. Now
as the whole sum 7i 89 chains : 22. 734 :: 85 Links : 2. 453 miles = Fd, the distance of the
point d from F where the Line crossed the chord DG : and it must cross the Parallel when
the offset from the chord DG is = to the offset in the Triangle dDF viz. at t. From the
whole the quantities of the Triangle dDE, dGL and LMN (to which add GL = HN constant)
corresponding to the intermediate miles are had by proportion.

From the foregoing computation of the stars we find we are 6 chains 94 links to the
Northward. Then to be in the true Parallel at 10’ = 11. 37 miles West
we change the direction found by the stars on the 16th and 17th August thus
as 11. 37 miles : 6. 94 chains :: 45. 62 chains = Radius we measured : 34. 7 Links. This
quantity we laid off to the Southward at Right Angles to the direction Figure

found by the stars, and in this direction proceeded to run as follows. 1

104

1765

August

20

Began to Run the Line in a direction to be in
the true Parallel at 10' = 11. 37 Miles West.

21

23

Miles

Chains (Links)

At

f 1

61

Crossed Piney Run

171

61

70 Crossed Ditto

71

62

25 Crossed Ditto

71

63

Mr. Stephen Grise's House

72

38

Crossed Piney Run

72

77

Crossed Ditto the last time

Continued the

Line

(73.58

Crossed Monocacy Road

At

<74.28

Mr.

Michael Miller's House 4 chains North

(74.63

Mr.

Henry Bower's House 2 chains North

Continued the

Line

(76.00

Crossed Willollowey's Creek

At

<76. 5

Mr.

William Davis's House 7 Chains North

(76.42

Mr.

Thos. McCewn's House 50 Links South

7 Chains North of the Line

Continued the Line

At 78. 66 crossed Rock Creek. This creek here 2 chains wide,
two chains South where we crossed; Mash Creek joins Rock Creek.

Continued the Line

79. 56 Mr. John McKenley's House 2 chains South

80. 21 crossed Mash Creek. Breadth near two chains.

Sunday

Continued the Line

At 81 miles 32 chains Mr. John Everett's House 12 chains North

81 miles 59 chains Mr. John Young's House 5 chains North

82 miles 66 chains crossed Middle Creek

82 miles 77 chains Mr. Matthew Elder's House 1 chain 50 Links South

Supposed to be in the 83 miles 13 chains 96 links changed our direction to be

true Parallel again in the true Parallel 10' West as by the following computation.

Here BP, AP and DP = Computed true parallels 50° 16' 40" (near enough for this purpose)
PS * Complement of the Latitude at the Sector = 50° 16 1 35"42
SC the direction found by the Stars on the 16th and 17thiof August, Instant.

SN = 45 chains 62 links = a Radius measured

which gives NM = 34. 7 Links as by the leaf before. (log)

156

Then as 45 chains 62 links
: Rad

:: 34. 7 Links

: Tangent angle NSM 26' 10"

Angle PSC 89°55' 51"

Angle PSA = 90022' 01"

(log)

As Rad =10.

to 40 chains = 4000 links = 3. 6020600
:: Sine dAo 34' 29”7 = 8.0015379

to do 40. 14 links = 1. 6035979

3. 6591553

10 .

1. 540329 5 r
7. 881>lfT42

Then as Sine AP 50° 16' 40”
To Sine Angle PSA 90° 22' 01"
So is Sine PS 5Q° 16' 35i'42

= 9,

9

(log)
8860120
9999911
8860039. 85

19.8859950.85

9.9999830.85

89°55' 51”
1790 25' 30L'3
180° 00' OOl’O

which

To Sine Angle SAP 89° 29' 39. 3"

Add Angle PSA =

Angle BAP

Subtract from _

Rest 00° 34' 29’.'7 Angle dAp which
we must lay off from our direction SAd
to give AB for to be again in the true
Parallel 10 ,r West* This angle as 40 chains.
Radius = Ad gives do = 40. 14 Links which we laid
off, etc., etc. to the Northward, and
proceeded to run AoB as follows.

Figure

157

105

1765

August

27

28

29

30

31

Continued the Line
84 miles 46 chains,
Continued the Line

84 miles 74 chains

85 miles 51 chains
Continued the Line

86 miles 41 chains,
86 miles 44 chains,

86 miles 72 chains,
Continued the Line

87 miles 75 chains,

88 miles 00 chains,
Continued the Line

in the direction last found.

Mr. Thomas Scot's House 5 chains South

crossed Flat Run

Mr. James Stevenson's House 5 chains North.

Mr. William Brown's House 2 chains North

Crossed Tom's Creek. The foot of the South Mountain.

Mr. Phineas Davidson's House 1 chain North.

Crossed Friends Creek in the South Mountain.

Mr. John Chohorn's House one chain North in Ditto.

September

1 Sunday

2 Continued the Line

3 Continued the Line

At 92 Miles 4 chains Mr. George Craft's House 6 chains North in the Mountain.

4 Continued the Line

At 93 (miles) 63 chains crossed the 1st spring running into Antietam.

94 (miles) 62 chains crossed a Spring running in to Ditto. This Spring
is at the foot of the South Mountain on the West side.

94 miles 62 chains 68 links. The Post on which the Transit Instrument was
fixed to Find the Direction.

5 Brought the Sector to the West Side of the Mountain.

6 Set up the Sector in our direction at the distance

of 94 miles 63 chains 10 links from the Post marked West in Mr. Bryan's field,
and made the following observations. Cloudy.

158

Plane of the Sector East

Star Name

Nearest Point

Revolutions

Difference

Apparent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

n

i

it

o

!

It

Delta Cygni

4

50+

5

14+

0

55.8

4

50

55.8

4

10. 5

Gamma Cygni

0

15-

5

10.5

2

54. 0

0

12

06.0

1

44.5

Alpha Cygni

4

45-

3

41.5

1

6. 0

4

43

54.0

5

3.5

Capella

6

00+

6

35.5

0

30.5

6

00

30.5

6

5

Cloudy

Alpha Lyrae

1

10-

6

50+

1

32.3

1

08

27.7

5

10

Delta Cygni

4

50+

3

28-

0

56. 0

4

50

56.0

2

24-

Gamma Cygni

0

15-

4

39+

2

57.3

0

12

02.7

1

18

Alpha Cygni

4

45-

6

21+

1

04. 4

4

43

55.6

7

34-

Capella

6

00+

7

23+

0

31.8

6

00

31. 8

6

43.5

159

106

And 23 43 46

+6 11 -
+0 7+

+0 1= what the star's Right Ascension has

_ gained since 1st June

23h 50m 05s Aldebaran will be on the said azimuth

When Alpha Arietis passed the middle wire of the Transit Instrument was brought
to it as usual, and a mark at the distance of 49 chains 10 links
placed; when the other two stars passed at the above times,

they bisected the mark 1st placed, that it could not be altered for the better. 160

10 Star Name Nearest Point Revolutions Difference Apparent

on the Sector and Seconds on Zenith Dist ance

the Micrometer

Alpha Lyrae 1 10- 5

4

Delta Cygni 4 50+ 2

1

Gamma Cygni 0 15- 5

2

Alpha Cygni 4 45- 4

5

Capella 6 00+ 11

10

11 Gamma Cygni 0 15- 8

4

Alpha Cygni 4 45- 5

7

Capella 6 00+ 10

10

12 Alpha Lyrae 1 10- 9

7

Delta Cygni 4 50+ 7

6

Gamma Cygni 0 15- 6

3

M

ii

o

i

44

5+

30. 7

1

08

29.3

11.5

6+

0

57.2

4

50

57.2

30

13

2

53.0

0

12

07.0

25.5

37+

1

3. 8

4

43

56.2

7

27-

0

32. 3

6

00

32.3

11.5

48+

2

51.2

0

12

8.8

40+

2.5

1

6.2

4

43

53.8

47+

16+

0

31.0

6

00

31.0

30

43-

1

31.3

1

08

28.7

32.5

29-

0

55. 8

4

50

55.8

50.5

35

2

51. 5

0

12

8.5

107

Turned the Sector Plane West

1765

September

13

15 Sun.

16

Star Name

Capella
Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Capella
Alpha Lyrae
Gamma Cygni
Alpha Cygni
Capella
Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Capella
Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Capella

Nearest Point
on the Sector

o

6 0+

1 10 -
4 50+

0 15-

4 45-

6 00 +

1 10 -
0 15-

4 45-

6 0 +

1 10 -
4 50+

0 15-

4 45-

6 00 +

1 10 -
4 50+

0 15-

4 45-

6 00 +

Revolutions
and Seconds on
the Micrometer

R

tt

6

6+

6

44

8

26+

10

18.5

10

25.5

11

34

11

32+

15

1+

13

33. 5

12

29

8

51-

9

36. 5

14

30.5

16

26

13

28+

16

51

15

35

14

28. 5

10

40

11

27

11

40

13

32. 5

14

15-

15

25

15

14

18

37-

7

50.5

43-

8

12. 5

8

50

8

18-

10

10-

11

6

12

14

10

46-

14

15+

13

2

11

44

12

47

13

32. 5

18 Computing our observations as follows.

19 Packing up the Instruments, etc., etc.

Difference Apparent

Zenith Distance

o l

0

37.7

6

00

37.7

1

36.2

1

08

23.8

1

00.5

4

51

00.5

2

57. 0

0

12

03.0

0

56.5

4

44

03.5

0

37. 8

6

00

37.8

1

39. 5

1

08

20.5

2

58.7

0

12

01.3

0

58.5

4

44

01. 5

0

39. 0

6

00

39.0

1

36.5

1

08

23.5

1

02.3

4

51

02.3

2

58.7

0

12

01.3

0

59. 8

4

44

00. 2

0

37.5

6

00

37.5

1

36.0

1

08

24.0

1

00.0

4

51

00.0

2

57.6

0

12

02.4

1

02.0

4

43

58.0

0

37. 5

6

00

37.5

108

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109

i:'54

TS5

■0"77
2!'79 r 5

average = 01'56 Hence

(Undated) Hence the offsets at every Mile Post, 'betwixt this Station and where the
Sector was set up August 7th, 1765, as follows,.

Miles from the

Offsets for the

Offsets for the

True offsets to

Post marked West

Circular part

Triangle NdH

the true

Parallel

IPH and XPL

Links

Chains

Links

Chains

Links

71.54

0+

6

94 \

o

6

'94 South

72

4

6

65 \

3

6

69

73

12

6

00 \

TO

0>

6

12

74

18

5

37 \

<-K

TO

5

•55

75

22

4

74 \

2“

4

96

76

25

4

11 \

0

3

4

m

77

27

3

48 /

Q.

3

75

78

27

2

85 /

2

3

12

79

25

2

21 /

o

2

46

80

21

1

57 /

a

1

78

81

16

0

94 /

1

1(0

82

9

0

31 /

0

40 South

82.495*

5

0

00

0

0 5 South

83

2

0

32 \

O

3 0 North

changed at 83. 174

0-

0

43 \

s

0

43

84

6

0

46 \

%

0

40

85

14

0

50 \

TO

0

36

86

20

0

53 \

?

o

0

33

87

24

0

57 \

B

0

■33

88

26

0

61 \

D

0

35

89

27

0

64 }

*

0

37

90

25

0

68 /

c+

o

0

42

91

23

0

72 /

»—•

0

49

92

19

0

75 /

0

56

93

13

0

79 /

0

66

94

5

(0

83 j

0

78

94.789

0

0

85 (

0

85 North

♦Crossed the chord IH at 82.495 164

(Undated) Here HpIPL, the true Parallel of Latitude. N, the Sector at the last Station.

K at this and NDK the Line run. D, the Point changed at.

The Point a
Whole lino

K = 71. 54 miles
K= a-5 r 789
= 23. 240

NH - 6. 94 chains North PointjD = 83.174 miles

&L = 0. 85 South (N = 71.540

DN = 11.634 subtract 11.37 miles

rest = 0. 264 mile what we have over run the usual change at an angle of 34* 291*7 (vid minutes

26th of August) Hence we are more South than we should have been if the ground would have admitted

us to have changed at the 10' West.

Points K= 94.789

D = 83. 174

DK = 11.615 Then as 23.249 miles : 85 links :: 11.615 miles : 42 links. Then
85 - 42 = 43 = Dl the offset to the North at the change. O as 23. 249 : 85 :: 11. 634 = ND : 43.
Now having KL = 0. 85 chain and DI = 43 links, the intermediate offsets corresponding to the miles
are had from EMC to IL by proportion as 11.634 miles : 6. 94 chains f 85 links :: 43 links : 0. 679 miles.
Then 11. 634 miles less . 679 miles = 10.955 milessdN which corresponds to the error 6. 94 hence the
offsets for the intermediate miles from dN to IH by proportion.

To the point N - 71. 54 miles

add dN = 10. 955

Gives the point = 82. 495 miles where the Line ND crossed the chord IH. Then

for the offset at = 83.000

0. 505

As 0. 679 mile : 43 links :: 0. 505 mile : 32 Links = be = the offset at the 83 mile
to the chord IH from DN Northward. From the whole the separate parts of
the Triangle corresponding to the miles as by the Table.

Figure

165

110

1765

September

20 Began to run the Line in the direction found by the stars on the 9th instant
Corrected by 9 links laid off to the North at the distance of 2 miles 32 chains
to account for the error at the Sector 85 links South, that is, to be in the
Parallel at 20' West.

21 Continued the Line.

95 miles 38 chains crossed a spring running into Antietam.

96 miles 3 chains. Mr. Staphel Shockey's House 7 chains North.

22 Sun, Went to see a cave (near the Mountain about 6 miles South of Mr. Shockey's.)

The entrance is an arch about 6 yards in length and four feet in height, when
immediately there opens a room 45 yards in length, 40 in breadth and 7 or 8
in height. (Not one pillar to support nature's arch): There divine service is
often (according to the Church of England) celebrated in the Winter Season.

Ch the sidewalls are drawn by the Pencil of Time, with the tears of the Rocks:

The imitation of Organ, Pillar, Columns and Monuments of a Temple; which, with
the glimmering faint light; makes the whole an awful, solemn appearance: Striking
its Visitants with a strong and melancholy reflection: That such is the abodes of
the Dead: Thy inevitable doom, O stranger; Soon to be numbered as one of them.

From this room there is a narrow passage of about 100 yards, at the end of which
runs a fine river of water: On the sides of this passage are other rooms, but not
so large as the first.

23 Continued the Line

99 miles 35 chains crossed Antietam Creek.

24 Continued the Line

101 miles 71 chains Mr. Samuel Irwin's Spring House, 2 chains North.

102 miles 34 chains Mr. Michael Walker's House 4 chains North.

102 miles 67 chains A great Spring running into Antietam.

102 miles 70 chains Mr. William Duglass' House 4 chains North.

25 Continued the Line

103 miles 69 chains Crossed a Road leading to Swaddingem's Ferry (or_ Ferry)

on Potowmack.

26

27

28

29 Sun.

30

October

1

2

Continued the Line

105 miles 78 chains 67 links changed our direction 8' 18 M North by laying off
9. 65 links at the distance of 33 chains 77 links.

106 miles 4 chains. Mr. Ludwig Cameron's House 4 chains North.

Continued the Line

Continued the Line

103 miles 5 chains Crossed the Road leading from Carlisle to William's Ferry on
Potowmack (near Watkin's Ferry)

At the River Potowmack. Forded it at the above Ferry; here Conecocheague falls
into the said River about seven miles to the South of our Line.

On the Virginia Side is a Log Fort and a Tavern. The River here is about 200 yards
wide.

Continued the Line.

108 miles 65 chains Mr. Thomas Meeks House 2 chains South

109 miles 14 chains Crossed Conecocheague Creek. Two chains in breadth.

Continued the Line
Continued the Line
112 miles 20 chains
Continued the Line
114 miles 00 chains

166

3

Crossed a Road leading from the Temporary Line to Frederick Town.
Mr. Philip Davis's House one mile and a half North by Estimation.

167

1765

October

4

5

6
7

Continued the Line

115 miles 42 chains Crossed a small spring, at the foot of the North Mountain.

Continued the Line

Sunday

Set up the Sector in our Direction at the Distance of 117 miles 12 chains 97 links
from the Post marked West in Mr. Bryan's Field and made the following observations.

Plane of the Sector East

Star Name

Nearest Point

Revolutions

Difference

Apparent

on the S

ector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

it

i

it

o

i

ii

Capella

6

0+

10

33-

0

39.0

6

00

39.0

Cloudy

9

46-

Very faint

Cloudy

(Alpha) Lyrae

1

10-

10

45.5

1

37.5

08

22.5

9

00

Delta Cygni

4

50+

8

7 .

1

7.5

4

51

7.5

6

43.5

Gamma Cygni

0

15-

7

41

3

4.5

0

11

55.5

4

12.5

Alpha Cygni

4

45-

5

31+

0

52.7

4

44

7.3

6

32

Capella

6

00+

10

20

0

43. 5

6

00

43.5

28.5

11

Alpha Lyrae

1

10-

9

0-

c

1

38.7

1

08

If

21.3

Delta Cygni

4

50+

6

0

31

1

6.7

4

51

6.7

5

16+

Gamma Cygni

0

15-

7

9. 5

3

03. 0

0

11

57.0

3

34. 5

Alpha Cygni

4

45-

4

Ot

0

55.0

4.

44

5.0

Capella

6

00+

6

10. 5

0

42. 8

6

00

42. 8

5

20-

12

Alpha Lyrae

1

10-

9

26

1

38.0

1

03

22.0

7

32

13 Sun.

Alpha Lyrae

1

10-

10

14+

38.3

1

08

21.7

8

20

Delta Cygni

4

50+

6

39

1

5. 5

4

51

5.5

5

25.5

Gamma Cygni

0

15-

4

40-

3

02.7

0

11

57.3

1

13

Alpha Cygni

4

45-

7

49+

0

52.2

4

44

7.8

8

49.5

Capella

6

00+

10

30+

0

43.3

6

00

43.3

9

39

14

Cloudy

15

Cloudy

16

Alpha Lyrae

1

10-

9

49+

1

35.3

1

08

23.7

8

5

Delta Cygni

4

50+

6

37

1

6.3

4

51

6.3

5

23-

169

112

1765

October

17

18

19

20 Sun.

21

13 Sun.

20 Sun.

22

Turned the Sector Plane West when Alpha Lyrae passed the wire, it appeared by the
clock to be within 20" (of time) of the meridian. We therefore took Alpha Lyrae
thus: J

Star Name

Nearest Point

Revolutions

Difference

Add are nt

on the S

ector

and S

econds on

Zenith Distance

the Micrometer

o

i

R

n

o

it

o

Alpha Lyrae

1

10-

4

32.5

1

45. 8

1

08

14.2

6

34+

Gamma Cygni

0

15-

6

49+

3

10.2

0

11

49.8

10

31.5

Alpha Cygni

4

45-

9

16. 5

0

46. 5

4

44

13.5

8

22

Cloudy

Alpha Lyrae

1

10-

5

36-

1

44.3

1

08

15.7

7

35

Alpha Cygni

4

45-

3

40+

0

48.0

4

44

12. 0

2

44+

Cape 11a

6

00+

3

33

0

49.5

6

00

49.5

4

30.5

Cape 11a

6

00+

5

42-

0

50.6

6

00

50.6

6

40+

Alpha Lyrae

1

10-

8

10.5

1

42. 5

1

08

17.5

10

9

Delta Cygni

4

50+

11

1-

1

12. 8

4

51

12. 8

12

21.5

Gamma Cygni

0

15-

13

24-

3

11.6

0

11

48. 4

17

7+

Alpha Cygni

4

45-

15

30

0

46.7

4

44

13.3

14

35+

Cape 11a

6

00+

8

40.5

0

51.2

6

00

51.2

9

40-

170

For the direction at our Station 117 miles from the Post marked Wesl

Time by Clock

Clock gains

per day

18h

46m

00s

lm

19s>

18

47

19

f

19

55

33

lm

17s

19

59

23

5

26

1,5

lm

16.5;

5

27

18

18

56

28

20

5

3.5

21

0

54

18

57

42

lm

14

20

.6

17

lm

13.5

21

2

8-

lm

14

20h 20m

33s

21h~39m

13

21m

50s

40m

34

23m

12s

41m

51s

Alpha Lyrae Ditto
Delta Cygni Ditto
Alpha Cygni Ditto

s Alpha Lyrae Ditto

s 42h 02m 25s 1

s 42h 02m 24s > Equal altitudes. Alpha Cygni
2m 24s )
in 21h 01m 12s

20h 33m 28 s = Right Ascension Alpha Cygni
27m 44s Clock fast for sidereal time

113

1765

October

21h 53m

03 s

= Right Ascension Mid-Heaven when Alpha Arietis on the Azimuth

+ 0

1

= Difference in Right Ascension Alpha Arietis from first day of June

+ 0

4.5

+27

44+

22h 20m

52.5s

= Time by the clock when Alpha Arietis will be on the Azimuth from
the North of 90° 04* 09"

23h 39m

19

- Right Ascension Mid-Heaven Eta Pleiades (Tauri)

+ 0

1

+!!7

44

+ 0

10

24h 07m

14. 5s

= Eta Pleiades (Tauri) on the Azimuth 90° 04* 09"

23h 43m

46s

= Right Ascension Mid-Heaven when Aldebaran on Ditto

+ 0

01

for change in Right Ascension

+ 27

44+

+ 0

10+

24h 11m

42s

= Aldebaran will be on the Azimuth of 90° 04' 09"

by the clock. When Alpha Arietis passed by the

clock we placed a mark at the distance of 52

chains 68 links by the Transit instrument as usual,

and when Eta Pleiades (Tauri) and Aldebaran came to the

Azimuth it fell so near, that the mark could not be altered.

22

Proved the direction found last night thus

Time by clock

2Oh 23m 34s

21h 38m 39s

42h 04m 52s

24

52

40

00

04 52

26

13.5

41

19

04 53-

21h 02m 26. 5s
20h 33m 28s
28m 58. 5s

Alt. of Alpha Cygni

Right ascension of star
Clock fast

as 24h i lm 14s :: 80m : 4s

21h 53m 04s = Right Ascension Mid-heaven when Alpha Arietis is on the Azimuth

+28m 58.5s
+Q0m 04s

22h 22m 06.5s = Time by the c lock when on the Azimuth

23h 39m 20s =

+28m 58. 5s
+ 0m 10s
24h 08m 28. 5s -

Right Ascension Mid-Heaven when Eta Pleiades (Tauri)is on Azimuth
as 24h : lm 14s :: 190m : 10s

Time by the clock when on Ditto (i. e,, on the required Azimuth)

23h 43m 47s Right Ascension Mid-Heaven when Aldebaran is on Azimuth

+28m 58. 5s
_ + 0m 10s

24h 12m 55. 5s = Time by the clock when on Ditto

At the above times the wire in the Transit Instrument was set to
the star as usual ai^d they all agreed within four inches of the
mark placed last night.

N. B. The mean of these two nights observations (that is the middle of
the four inches) is five feet 11 inches South of the Notch in the
tree made in our Line: From the Notch may be discovered next season
whether the mark set by the stars is altered or not. 172

114

Plane of the Sector West

1765
October

22 Star Name Nearest Point Revolutions Difference Apparent

on the Sector and Seconds on Zenith Distance

the Micrometer

R " " o • *»

Alpha Lyrae

10 -

9

13-

1

42.8

1

08

17.2

11

11.5

Delta Cygni

4

50+

11

51

12.3

4

50

12.3

13

19+

Gamma Cygni

0

15-

14

5+

3

9. 7

0

11

50.3

17

39

Alpha Cygni

4

45-

12

1.5

0

47.2

4

44

12. 8

11

6+

Capella

6

00+

11

3.5

0

49.5

6

00

49.5

12

1

Alpha Lyrae

10-

10

27.5

44. 8

1

08

15.2

12 28+

24 Computing our observations as follows

25 Computing offsets, etc. Went to Captain Shelby’s to desire him to go with us on
the North Mountain for to show us the course of the River Potowmack Westward.

26 Packed up our Instruments and left them (not in the least damaged to our knowledge)
at Captain Shelby's. Repaired with Captain Shelby to the Summit of the Mountain

in the direction of our Line, but the air was so hazy prevented our seeing the course
of the River.

27 Sun. Captain Shelby again went with us to the Summit of the Mountain (when it was very

clear) and showed us the northernmost bend of the River Potowmack at the Conoloways;

from which we judge the Line will pass about two miles to the North of the said River. 173

Plane of the Sector East

13 Sunday
16

Mean 12d

Aberration

Deviation

Precession

Refraction

Mean Zenith Distance
1st January, 1764, Plane East
17

19

20 Sunday

21
22
23

Mean 2 Oh

Aberration

Deviation

Precession

Refraction

Mean Zen. Dist. 1 Jan. 1764, Plane West

Ditto Plane East

True Zen. Dist. 1 Jan. 1764

Ditto at Post Marked West

Difference

15h

15m

Alpha Lyrae Delta Cygni

lh

08m

22.5s

21.3

22. 0

21. 7

23. 7

10

11

13

16

4h

51m

7.5s

6. 7

5. 5

6.3

lh

08m

22.24s

12d

18h

4h

51m

6. 50s

+ 17.07

-18. 37

- 8.34

+ 6. 70

+ 4 48

-14.72

+ 1.20

+ 5.60

lh

08m

36.65s

4h

50m

45.71s

lh

08m

14. 2s

17

lh

08m

15.7s

19

20

17.5

21

4h

51m

12. 8s

17.2

22

51

12. 3

15.2

lh

08m

15.98

21h

18m

4h

51m

12.55s

+ 16.26

-18.05

- 8.34

+ 6. 70

+ 4.50

-14.90

+ 1.20

+ 5.60

lh

08m

29.60s

4h

50m

51.90s

36. 65s

45.71s

lh

08m

33.12s

4h

50m

48.80s

lh

08 m

41.80s

40. 40s

08.68 So.

08. 40 So,

8.40
8. 14
9.00

_ 8. 15

Mean 8. 474 = 847. 4 feet

174

115

1765

October

10

11

13 Sunday

Mean

Gamma Cygni

O I M

Alpha Cygni
o i "

Cape 11a

17

19

20
21
22

Aberration
Deviation
Precession
Refraction
Mean Zen. Dist.

1st Jan. 1764, Plane East

Mean

Aberration
Deviation
Precession
Refraction
Mean Zen. Dist., 1 Jan. 1764
Ditto Plane East
True Zen. Dist., 1 Jan. 1764
Ditto at Post Marked West
Difference

0

n

55.5

10

4

44

7.3

10

6

00

43.5

57.0

11

5.0

11

42. 8

57.3

13

7.8

13

43.3

lid

15h

0

n

56.60

lid

15h

4

44

6.70

lid

23h

6

00

43.20

+17.33

-17.76

+ 5.46

.- 5.62

+ 5.06

- 9.23

+ 19.77

-22.14

- 9.41

+ 0.20

+ 5.50

+ 7.00

0

12

28.28

4

43

37.36

6

00

37.02

Plane West

0

11

49. 8

17

4

44

13.5

49. 5

19

44

12 . 0

19

6

00

20

6

00

50.6

0

11

48.4

21

13.3

21

51. 2

50.3

22

12.8

22

49. 5

20 d

7h

Ho"

11

49.50

20 d

lh

4

44

12.96

21 d

23h

6

00

50.20

+ 17.35

-18.00

+ 4.45

- 5.62

+ 5.06

- 9.23

+20.02

-22.41

- 9.53

+ 0.20

+ 5.50

+ 7.00

IT

12

21.45

4

43

43.05

6

00

42.89

00

CM

00

CM

37.36

37. 02

T

12

24.86

4

43

40.20

6

00

39.95

33.00

31.20

31.80

8 . 14S

9.00S

8 . 15S

Mean for all stars = 8" 474 = 847.4 feet = 12 chains 84 links = what we are to the South of the true Parallel.

(Undated) Hence the offsets at every mile post to where the Sector was set up on the 6th of
September as follows :

Miles from the Post

Distances from

Distances from

True Offsets

Marked West

the chords AB and

SED to the chords

BC to the circle

AB and BC

Chair

Links

94.789

0 -

0.85

0

85 North

95

3

0.96

0

93

96

12

1.50

1

38

97

18

2.04

1

86

98

22

2.57

2

35

99

25

3. 11

2

86

100

27

3.64

3

37

101

27

4. 18

3

91

102

25

4.72

4

47

103

21

5. 26

5

05

104

16

5.79

5

63

105

9

6.32

6

23

Changed the 105. 983

0

6.85

6

85

direction 106

8

6.87

6

79

107

14

7.41

7

27

108

20

7.94

7

74

109

24

8.47

8

23

110

26

9.00

8

74

111

27

9.54

9

27

112

27

10.08

9

81

113

26

10.62

10

36

114

23

11. 15

10

92

115

19

11.68

11

49

116

12

12.22

12

10

117

2

12. 76

12

74

117.162

0

12.84

12

84 North

116

(Undated) Here AbC the true Parallel, AB and BC chords. S the Sector at the South Mountain
and D at the North. Spd a Parallel 85 Links South of the true Parallel SED the
line run from the South to the North Mountain.

E the point changed at = 105.983 miles DC = 12 chains 84 links

Point S 94. 789 SA = 0 chains 85 links = pB = dC

SE =11. 194 miles 11 chains 99 links = dD

Point D = 117. 162 miles

S = 94. 789 m iles

Whole line = 22.373 miles

Then as 22. 373 : 11. 99 chains :: 11. 194 : 5. 99 chains = Ep to which add pB = 85 links gives
EB 6 chains 85 links the offset at the Change. Now having SA, EB and DC, the
offsets from SE to the chord AB and from ED to the chord BC corresponding to the
intermediate miles are had by proportion from which subtract all the way, the chord
from the circle; rest the true offsets from SED to the circle as by the Table.

NOTE: Here we changed so near 11. 37 miles from S, and the angle changed being but Figure

8 ' 18", there is nothing material to account for on that part. 177

1765

October

27 Sun, From here we could see the Allegany Mountain

for many miles, and judge it by its appearance
to be about 50 Miles (in) distance in the direction
of our Line.

28 Set out on our return to the River Susquehanna to
make the offsets from our Visto to the True Line.

Set off the offsets to the 109 Mile Post.

29 Set off Ditto to the 96 Mile Post.

30 Set off Ditto to the 87 Mile Post.

31 Set off Ditto to the 74 Mile Post.

November

1 Set off Ditto to the 63 Mile Post.

2 Set off Ditto to the 50 Mile Post.

3 Sunday

4 Set off Ditto to the 38 Mile Post.

5 Set off Ditto to the 29 Mile Post.

6 Set off Ditto to the 27 Mile Post: which is near to

the River Susquehannah on the West Side. 178

7 At Peach Bottom Ferry

8 Discharged all hands in order to meet the Gentlemen Commissioners
on the 16th Instant at York.

9 At Peach Bottom Ferry

10 Sun. At Ditto

11 Left Ditto

12 At York

13 At York

14 At York

15 At York

16 Attended the Gentlemen Commissioners

17 Sunday

18 Attended Ditto

19 Attended Ditto

20 At York

21 Left York and proceeded for the Middle Point to
set 50 Stones (one at each mile) in the Tangent Line

December

5 At Mr. Twifords on the River Nanticoke

17 Twenty stones arrived at Mr. Twiford's on the River Nanticoke; and about the

same time thirty were landed near the Bridge on the River Choptanck.

93

117

1766

January

1 The Stones all set. Left off for the winter season.

4 At Philadelphia

5 Sunday

6 Wrote to the Honorable Proprietors of Maryland and Pennsylvania.

7 At Brandywine

February

21

22

23 Sun,

24

25

26

27

28

Left Brandywine and proceeded for curiosity to the Southward to
see the country.

Crossed the River Susquehannah at Nelson's Ferry (about 7 miles
North of the Line). The Ferry is about 100 yards wide, the River
being pent in by two very lofty Hills. At 15 or 20 yards from the East Shore
170 Fathoms of Line with a very heavy weight, has been let down; but no
bottom could ever be found.

At Mr. William Lawson's near the Blue Ball in the Barrens (Borough) of York.

At Tawney Town,

At Frederick Town in Maryland near the South Mountain.

At Alexander (Alexandria) or Belheaven (Bell Haven) on the River Potowmack and
crossed the said River at Ditto in to Virginia.

Passed through Colchester and Lodged at Dumfreys.

At Stafford Court House^

March

1

2 Sun.

3

4

5

6

7

8

9 Sun.

10

11 & 12

13

14

Near Port Royal on the River Rappahannock.

Crossed the said River and lodged near the Fort Bridge. Saw green peas in the
fields five or six inches high.

Crossed the River Pomonkey at Claybourn 1 s Ferry. This is a beautiful situation
on the Bank of the River: opposite the door in a Right Line over the River is
a causeway of a Mile in Length, thro a mark (marsh) that is overflowed at High
Tide about three feet, and if taken in, I think it would be very rich pasture.
Reached the City of Williamsburg, the Metropolis of Virginia.

Wrote from hence to Mr. Williams: and left the City.

Near Tod's Bridge.

At Port Royal on Rappahannock at 3h 29m P. M. The Sun Shining in my face
I saw a streak of Lightning from 10° altitude down to the Horizon.

Crossed Potowmack at Hoe's Ferry. The River here about 3 miles wide.

Lodged near Port Tobacco.

Near Upper Marlborough.

Near London Town. Rain and Snow.

Near London Town. Rain and Snow
At Annapolis, the Metropolis of Maryland.

At Ditto. Compared with his Excellency Horatio Sharpe, Esq. (Governor)
a copy of our Journal.

Ditto.

April

9 The 9th April 1766. At 8h 06m P. M.

by the watch, a comet (meteor) (appeared.)
in a vertical with Beta Aurigae. At 8h 21m
a small star set over the trace as did
the comet at the above time.

NOTE: The small star set about 2 degrees to the
Northward of the comet.

Captain Shelby's watch (set this Evening by the Sun)
16 m faster than mine.

10 10th at 9h 01m Captain Shelby's watch 18m
faster than mine.

(Undated*

A page, mostly blank, containing some arithmetic.)

179

180

181

182

118

1766

March

15

17

18

21

29

30 Sun.

31

Left Annapolis and proceeded for the North Mountain
to continue the Line.

At Frederick Town near the South Mountain in Maryland.

J. D. (Jeremiah Dixon) left Philadelphia to attend the Gentlemen Commissioners
the 20th Instant at Chestertown in Maryland„

Received our Instructions to proceed with the Line to
the Allegany Mountain.

At Capt. Shelby's near the North Mountain.

At Capt. Shelby's near the North Mountain.

Messrs. Darby and Cope (Chain Carriers) with other Hands met at the North Mountain.

April

1

Changed the Direction found by the stars on the 21st and 22nd of October last,

to be in the true Parallel at 10' West. Thus

as 11. 37 miles : 12. 84 chains :: 52.68 chains : 74.36 links

This 74. 36 Links we laid off to the South of the mark left according to the stars
(it being to the Eastward 52 chains 68 links from where we left off last season)
and continued the Line in the Direction so changed.

Continued the Line.

Continued Ditto. At 118 miles 63 chains crossed the Head of little Licking Creek
running into Conecocheage.

Continued the Line. At 119 miles 18 chains (The summit of the North Mountain) Fort
Frederick in Maryland nearly south Distant about 8 Miles, and Fort Loudon (under
Parnel's Nob in Pennsylvania) nearly North, Distant about 11 miles.

At 119 miles 47 chains crossed the first Spring running in the Big Licking creek which
is on the West side of the North Mountain.

Continued the Line*

Snow
Rain'

Rain j
R ain I
Rain i
Rain '
Rain ,

Waiting for the Waggons and Tents; which were
prevented arriving by Weather, etc.

5

6 Sun.

7

8
9

10
11
12

13 Sunday

14 Mr. McLane came with the Waggons, Tents, etc.

15 Snow and Rain.

16 Continued the Line.

17 Continued the Line. At 121 miles 61 chains crossed a Road leading
from Fort Frederick to the little cove.

18 Continued the Line. At 122 miles 67 chains crossed Great Licking-creek,
foot of the North Mountain on the West Side.

At 123 miles 6 chains Mr. Brown's House 6 chains North.

Continued the Line.

at the

19

20 Sunday

21 Continued the Line,
of the Conoloways.

22 Continued the Line.

At 126 miles 71 chains crossed the 1st branch
Snow fell all the afternoon.

In the morning the Snow 4 inches deep in General.

183

i in

1766

April

23

24

25

26

Continued the line. At 128 miles 24 chains crossed the big Conoloway-creek.

At 129 miles 12 chains 04 links changed our direction to be again in the Parallel
at 10' West. Thus

(log)

As SM = Sm = 52 chains 68 links (see 1st April) = 3. 721646 Here P, the Pole : OAB

: Radius

:: NM = nm 74.36 Links
: Tangent Angle nSm = MSN = 48' 32"

Angle PSC = 89° 55' 51 n

Angle PSA = 89° 07' 19" Then

= 10 .

= 1.871339
8.149693

the true Parallel. S, the
Sector at the North Mountain
SCK the Parallel in at
the said Mountain, MSC the
direction we came in. MN

As Sine AP
: Sine PSA
:: Sine PS
: Sine of
Comp.

BAP =

Sum =

Rest

50° 16' 40"
890 07' 19"
50° 16' 48"47
89° 15' 37"
900 44 ' 23"
89° 55' 51"
180 u 40' 14"
-180° 00 ' 00 "

0° 40' 14"

be laid off from the direction

(log)

= 9.8860120
= 9.9999490
= 9, 8860268
9.9999638
= SAP = QAC
= PSC

the said direction changed which
we went off in. MN the
Quantity changed = 74. 36 Links
to the Eastward of S.

= BAQ which must

NSnAQ to the Southward, to give the direction or chord

AB, that is, to be again in the Parallel at 10' West.

(log)

Now as Rad

to 40 chains (4000 links)
:: Sine 40' 14"

: 46.8 Links

Then as 40 : 46. 8 links :

10 .

3.6020600

8.0684811

1. 6705411 The ground admitting we measured a Radius = 48. 23chains = Ap
: 48. 23 : 56. 43 Links. This we laid off from p to b and continued Figure

the Line in the direction A to B as follows.

184

The Sun's Limbs 6 h 11 m 25s
6 14 5

Set over the Allegany Mountain seen from the North
Mountain, distant about 50 miles

(indistinct) the apparent time. 185

(At 129 3/4 miles by estimation the
Continued the Line.< Northernmost bend of the River Potowmack
(Bore South distant about a mile and a half.

(130 miles 48 chains Mr. Edward Coomb's House 10 chains. North.

At <131 miles 20 chains Mr. Joseph Coomb's House 50 Links, North.

(132 miles 28 chains crossed the little Conoloway creek.

Continued the Line.

Continued the Line.

At 134 miles 54 chains The foot of Sidelong Hill (Here we could proceed no further with the waggons.)

135 miles 29 chains The Top of Ditto.

27 Sunday

28 Continued the Line.

At 136 miles 27 chains crossed little Bear-creek at the foot of Sidelong Hill
on the W»st side.

136 miles 50 chains crossed Big Bear Creek.

29 Continued the Line. At 138 miles 00 chains 40 links entered Sidelong Hill Creek.
Crossed the said creek three times and at 138 miles 50 chains left Ditto.

30 Sent for the Sector from Captain Shelby's.

1 (Blank)

2 The Sector brought to the East Side of Sidelong Hill.

3 Ditto brought to the foot of Town Hill on the East Side.

4 Sun. Set up the Sector (at Ditto) in our direction, at the distance

of 140 miles 15 chains 76 links from the Post marked West in Mr. Bryan's field
and made the following observations.

186

120

1766

May

5 Star Name

Plane of the Sector East

Nearest Point
on the Sector

Revolutions
and Seconds on
the Micrometer

Difference

Apparent
Zenith Distance

o

i

R

ii

ii

o

i

n

Alpha Lyrae

1

10-

5

23

1

5.0

1

08

55.0

4

10

Delta Cygni

4

50+

5

5

0

29.5

4

50

29.5

4

27.5

Gamma Cygni

0

15-

4

32-

2

29.7

0

12

30.3

1

38

Alpha Cygni

4

45-

1

38

1

29.0

4

43

31.0

3

23

Capella

6

00+

8

10-

0

47.7

6

00

47. 7 faint

7

14

Alpha Lyrae

1

10-

8

47-

1

3.2

08

56.8

7

35.5

Delta Cygni

4

50+

6

15+

0

29.8

4

50

29.8

5

37.5

Gamma Cygni

0

15-

7

27.5

2

29. 5

0

12

30.5

4

34

Alpha Cygni

4

45-

5

47.5

1

27.0

4

43

33.0

7

30.5

Capella

6

00+

8

43.5

0

46.5

6

00

46. 5 faint

7

49

Alpha Lyrae

1

10-

8

1 +

1

5.3

08

54. 7

6

40

Delta Cygni

4

50+

7

36

0

28.5

4

50

28.5

7

7.5

Gamma Cygni

0

15-

8

47.5

2

29. 5

0

12

30.5

6

2

Alpha Cygni

4

45-

7

37+

1

28.2

4

43

31. 8

9

21.5

Turned the Sector Plane West

Delta Cygni

4

50+

8

12

0

36.0

4

50

36.0

8

48

Gamma Cygni

0

15-

8

40

2

36.0

0

12

24.0

11

40

Alpha Cygni

4

45-

11

16. 5

1

23.0

4

43

37.0

9

37.5

Cloudy

Cloudy

Cloudy The Oak and Hickory Buds just breaking into Leaf*

Alpha Lyrae

1

10-

8

34

1

9.5

1

08

50.5

9

51.5

187

Alpha Lyrae

1

10-

5

50-

1

11.8

1

08

48.2

7

17.5

Delta Cygni

4

50+

5

28+

0

37.0

4

50

37.0

6

13+

Alpha Cygni

4

45-

6

47.5

1

24.5

4

43

35. 5

121

1766

May

13

For the Direction at our Station 140 miles from the Post marked West
Time by the clock

22 m

31s

llh

56m

46s

27

23

12

3

53

34

36-

8

54

46

4“

14 33

52-

49

27.5

37

54

53

20

41

15. 5

23h

31m

22 s)

31

16

Equal altitudes of Gamma Leonis

31

25 ;

llh

45m

41s

11

37

08 =

Right Ascension of Star

8 m

33s =

Clock fast for Sidereal Time

28

27

12 :: )

27

21.5 }

Equal altitudes of Arcturus

27

19 J

14

13

40

14

5

2 =

Right Ascension of Star

8

38

Clock fast

1766 May
Clock fast

14 51 15

{

+ 8
+ 0

38

1. 5

14

59

54. 5

16

17

28

+ 8

38

+00

04

16“

26

10

18

19

00

+ 8

38

+ 0

8.5

18

27

46. 5

* /Right Ascension Mid-Heaven when Gamma Leonis is on the azimuth
l of 89 55' 51" Westward from the North

= Time by the clock when on Ditto.

“ Right Ascension Mid~Heaven when Beta Leonis is on Ditto.

Time by the Clock when on Ditto
= Right Ascension Mid-Heaven when Arcturus on the Azimuth

Time by the clock when on Ditto.

When Regulus passed according to the clock we placed a mark as usual : its distance
from the Transit Instrument was 33 chains, 9 Links; and when Beta Leonis and Arcturus
passed we placed other marks. The extremes of the three were distant Eight Inches.

15

16

Star Name

Delta Cygni
Gamma Cygni
Alpha Cygni
Alpha Lyrae
Delta Cygni
Gamma Cygni
Alpha Cygni
Capella

Nearest Point
on the Sector

o 1

4 50+

0 15-

4 45-

1 10 -

4 50+

0 15-

4 45-

6 00 +

Revolutions
and Seconds on
the Micrometer

R

n

11

39.5

12

23+

11

31+

14

32

17

12

15

31

12

0 +

13

21 -

13

29+

14

16-

13

46.5

16

48-

1

2.5

17

22

9

19

10

16

Computing our observations as follows.

Difference Apparent

Zenith Distance

i

n

0

i

0

35.8

4

50

35. 8

2

36.7

0

12

23.3

1

25.0

4

43

35.0

1

12.4

1

08

47.6

0

38.4

4

50

38.4

2

37.2

0

12

22. 8

1

24. 5

4

43

35.5

0

49.0

6

00

49.0

122

1766

May

Plane of the Sector East

Alpha Lyrae

O l "

Delta Cygni

O , n

Gamma Cygni

O i ii

Alpha Cygni

O 1 n

Capella

O i

II

5

1

8

55.0

5

4

50

29.5

5

0

12

30.3

5

4

43

31.0

6

8

56.8

6

50

29.8

6

12

30.5

6

43

33.0

6

6

00

47.7

7

54.7

7

28.5

7

30.5

7

31.8

7

46.5

Mean

6d 16h

1

8

55.50

6d 16h

4

50

29.27

6d 17h

0

12

30.43

6d 17h

4

43

31.93

6d 14h

6

00

47. 10

Aberration

-13. 16

+16.20

-16.02

+17.13

- 2. 05

Deviation

- 7. 05

+ 5.28

- 4. 11

+ 3.43

- 8.48

Precession

+ 5.91

-19.41

+26.07

-29.21

-12.41

Refraction

+ 1.20

+ 5.60

+ 0.20

+ 5.50

+ 7. 00

Mean Zen.

Dist.

1

8

42.40

4

50

36.94

0

12

36.57

4

43

28. 78

6

00

31. 16

1st Jan. 1764

Plane East

Plane West

o

i

n

0

i

n

o

i

it

o

8

4

50

36.0

8

0

12

24.0

8

4

43

37.0

12

1

8

50. 5

13

8

48. 2

13

50

37.0

13

43

35.5

14

50

35.8

14

12

23.3

14

43

35.0

15

1

8

47.6

15

50

38.4

15

12

22. 8

15

43

35.5

16

6

00

49.0

Mean 13d 23h 1 8 48. 77 13d 4h 4 50 36.80 13d lh 0 12 23.37 13d 5h4 43 35.75 16d 2h 6 00 49.0

-11 fiO +15.15 -15.20 +16.42 - 0.80

Aberration

Deviation

Precession

Refraction

-11.60
- 7. 05
+ 5.96
+ 1.20

+ 15. 15
+ 5.28
-19.57
+ 5.60

-15.20
- 4. 11
+26.28
+ 0.20

+16.42
+ 3.43
-29.45
+ 5.50

- 0.80
- 8.48
-12.51
+ 7.00

Mean Zen. Dist.

1

8

37.28

4

50

43.26

6

12

30.54

4

43

31.65

6

00

34.21

1st Jan. 1764

Plane West

Ditto Plane East

1

8

42.40

4

50

36.94

0

12

36.57

4

43

28.78

6

00

31. 16

True Zen. Dist.

1

8

39. 84

4

50

40. 10

0

12

33.55

4

43

30.21

6

00

32.69

1st Jan. 1764

Ditto at the Post
Marked West

1

8

41.80

4

50

40.40

0

12

33.00

4

43

31.20

6

00

31.80

1.96

South

0.30

North

0.55

North

0.99

North

0. 89

South

Hence 1V96 - 0730 - 07 5 5 - Q'J99 + 0" 89 = O’.'20 = 20 feet =31 links
5

that we are South of the true Parallel.

190

(Undated) Hence the offsets at every mile Post to where the Sector was
set up on the 7th of October last as follows.

Miles from the

Circle from

Triang.

SRP

True

Post marked West

the chords

hence PB = 44

Offsets

AB and BC

Links must be

added constant

Links

Chains

Links

Chains

Links

117.162

0

12

40=SR

12

84

North

118

8

11

50

11

86

119

16

10

40

10

68

120

22

9

31

9

53

121

25

8

25

8

42

122

27

7

14

7

31

North

123

27

6

05

6

22

124

26

4

96

5

14

125

23

3

86

4

07

126

18

2

76

3

02

127

12

1

67

1

99

North

128

5

0

58

0

97

North

Changed the 129

4

0

2N

0

2 S For bd = 4 links = Circle

Direction 129m 12ch. 04 links

5

0

ns

0

16

from the chord and cb =

130

13

0

08

0

21

2 = Line from the chord

131

19

0

04

0

23

then cd = 2 * offset

132

23

0

00. 5

0

23.

5 from the Line.

1QO

26

0

03

0

23

27

0

07

0

20

27

0

11

0

16

136

26

0

15

0

11

South

137

24

0

19

0

05

South

138

19

0

22

0

03

North

139

12

0

26

0

14

North

140

3

0

30

0

27

North

Sector 140. 197

0

0

00

0

31

North 19

(Undated) Here ABC the true Parallel

AB and BC chords of 11.37 miles nearly
S the Sector at the North Mountain
N Ditto at Town Hill

SLN the Line run. P the point we should have changed at
if the ground would have permitted: L the Point we did change at
Then L = 129. 150 miles where we did change
P= 128. 532 = 117. 162 + 11. 37 miles

rest PL= 0, 618 - What we have over run at an angle of 40* 14" (see minutes
of the 23rd April) = KPL hence KL = 58 Links * MN : for LN and PM are Parallel
Then if we had changed at P our error would have been 58 t 31 = 89 Links = MC: Hence
as the whole length of the Line 23. 035 miles : 89 links :: 11.37 miles : 44 links = PB.

And as 23.035 : 89 :: 11.988 (= SP + PL) : 47 links = Kg

or as PM = 11.665 miles : (89 - 44) (= MC - PB) :: PL = .618 miles = PK : 3 links nearly.

Then 44 + 3 = 47 = Kg as before.

Now KL - Kg = 58 - 47 = 11 = gL = what we run to the North of the chord BC,
before we changed. Then as NC + gL = 42 links : LN = 11. 047 miles ::
gL =11 links : 2, 9 miles = LQ.

Then the point L = 129. 150 miles + 2. 9 miles = 132. 050 miles, the point Q where we passed
the chord BC. and where we passed the true parallel will be at D, where the offset
from the chord is = the offset in the Triangle NQC which falls at 137. 625 miles
As LK = 58 : PK = 0.618 miles :: gL:0. 117 = pg, then 129. 150 miles - 0. 117 = 129.033 miles
the point p, where the Visto crossed the chord BC.

From the whole, the Quantity of the Triangle NQC, gQL, gpL and pBP Figure

corresponding to the intermediate miles are had by proportion, as by the second column. 192

124

1766

May

17 Placed a mark to the Eastward (in the direction found by the stars on
the 13th Instant) so as to be seen from the Summit of Town Hill.

18 Sun. Packing up Instruments.

19 Continued the Line in the direction found by the stars, that is, to
be in the Parallel we are now in at 10' West.

At 140 miles 54 chains. The top of Town Hill.

20 Continued the Line.

At 143 miles 77 chains crossed 15 Mile Greek.

Continued the Line.

At 146 miles 52 chains. The top of Ragged-Mountain.

Continued the Line.

At 148 miles 21 chains crossed Old Town Creek.

23 ) Brought the Sector etc., from the Town Hill to the

24 / Warrior Mountain

25 Sunday

26 Continued the Line

At 149 miles 17 chains the top of little Warrior Mountain,

27 Continued the Line. At 151 miles 48 chains the summit of
the great Warrior Mountain. Here we changed our
direction 8' 18” to the Northward, that is, to be in the Parallel
we are now in at 10' West : thus

as 40 chains : 9. 6575 links (corresponding to the angle 8‘ 18") :: 1 mile 53 chains 87 links =

(Radius we measured) : 32. 31 links. This we laid off to the Northward from bur
direction on Flintstone Mountain.

At 151 miles 67 chains, crossed Flintstone Creek.

153 miles 21 chains 87 links, the top of Flintstone Mountain. s 193

28 Continued the Line.

At 154 miles 28 chains crossed a Run between Flintstone Mountain
and Evits Mountain

29 Continued the Line.

At 155 miles 33 chains. The Summit of Evits Creek Mountain

At 156 miles 69 chains, crossed the 1st Branch of Evits Creek.) These (last two) join about
At 156 miles 79 chains, crossed the 2nd Branch of Ditto. J 1/4 mile South.

Continued the Line.

At 157 miles 64 chains. The top of Nobbley Mountain.

At 157 miles 75 chains, crossed the Road leading from Fort Cumberland
to Bedford.

Continued the Line.

At 159 miles 71 chains The summit of Wills' Creek Mountain:

Here by the estimation of some who live near the place, Fort
Cumberland bears South, distant between 5 and 6 miles.

At 161 miles 25 chains crossed Wills' Creek: This creek in general about 30 yards
in breadth, and at this time 1.5 or 2 feet nearly in depth.

June

1 Sunday

2

3

4

194

125

1766

June

9

10

11

12

13

14

15 Sun,

Set up the Sector in the Direction of our Dine

at the distance of 165 miles 54 chains 88 links from the Post marked West
in Mr. Bryan's field, and made the following observations:

Plane of

the Sector EAST

Star Name

Nearest Point

Revolutions

Difference

Apparent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

o

t

R

n

i

it

o

i

it

Alpha Lyrae

1

10-

5

12-

1

16.4

1

8

43.6

3

39+

Delta Cygni

4

50+

7

2-

0

39.7

4

50

39.7

6

14

Gamma Cygni

0

15-

6

. 27

2

42.5

0

12

17.5

3

20.5

Alpha Cygni

4

45-

3

31.5

1

17.5

4

43

42. 5

5

5

Alpha Lyrae

1

10-

7

38-

1

15.0

1

08

45. 0

6

15-

Delta Cygni

4

50+

6

9-

0

40. 7

4

50

40.7

5

20

Gamma Cygni

0

15-

5

39+

2

41.3

0

12

18. 7

2

34

Alpha Cygni

4

45-

2

18

1

18.3

3

44+

Alpha Lyrae

10-

5

44

4

20

Delta Cygni

4

50+

3

39

0

41.3

4

50

41.3

2

50-

Gamma Cygni

0

15-

4

31-

2

41.7

0

12

18.3

1

25

Alpha Cygni

4

45-

17

40.5

17.5

4

43

42. 5

1

14

Turned the Sector:

Plane WEST

Star Name

Nearest Point

Revolutions an

Difference

ApDarent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

it

it

6

i

it

Alpha Lyrae

1

10-

1

14

20.7

1

8

39.3

2

43-

Delta Cygni

4

50+

2

18

0

45.7

4

50

45.7

3

12-

Gamma Cygni

0

15-

3

21

2

45.5

0

12

14.5

6

30.5

Alpha Cygni

4

45-

6

15-

1

14.2

4

43

45. 8

4

44. 5

Alpha Lyrae

1

10-

6

14+

21.4

1

8

38. 6

7

44-

Delta Cygni

4

50+

9

3- ::

0

49.6

4

50

49.6

10

0+

Gamma Cygni

0

15-

10

16-

2

46.8

0

12

13. 2

13

26. 5

Alpha Cygni

4

45-

5

42.5

13.5

4

43

46. 5

4

21

Alpha Lyrae

10-

5

10+

1

21.7

1

08

38. 3

6

40

Delta Cygni

4

50+

7

31.5 ::

8

31+

Gamma Cygni

0

15-

8

17

2

46.5

0

12

13. 5

11

27. 5

Alpha Cygni

4

45-

9

4-

1

14.4

4

43

45.6

7

33+

126

1766

Jun.3

16 \ Computing our observations, offsets, etc., as follows:

17 J Ditto

N. B.Capella passing the Meridian with the Sun, and the weather
in general a little hazy in the day time, prevented our

making any observations of that Star. 196

Plane of the Sector EAST

Alpha Lyrae Delta Cygni

o i " Of "

Gamma Cygni Alpha Cygni
o i " o » "

June

9

1

08

43.6

4

50

39.7

0

12

17.5

4

43

42.5

10

08

45.0

50

40.7

12

18.7

43

41.7

11

08

44.0

50

41.3

12

18.3

43

42.5

Mean

lOd 13h

1

08

44.20

4

50

40. 57

0

12

18. 17

4

43

42.23

Aberration

- 4.52

+ 8.69

- 9.62

+ 11.22

Deviation

- 6.86

+ 5.03

- 3.85

+ 3. 19

Precession

+ 6. 15

-20.18

+27.08

-30.35

Refraction

+ 1.20

+ 5.60

+ 0.20

+ 5.50

Mean Zen. Dist.

the

1

08

40.17

4

50

39.71

0

12

31.98

4

43

31.79

1st Jan. 1764

Plane WEST

June

13

1

08

39.3

4

50

45.7

0

12

14.5

4

43

45.8

14

08

38.6

12

13.2

43

46. 5

15

08

38.3

12

13.5

43

45.6

Mean

14d 13h

1

08

38.73

4

50

45.70

0

12

13.73

4

43

45.97

Aberration

for Alpha

- 3.38

+ 7.59

- 8.63

+ 10.26

Deviation

Eyrae

- 6.86

+ 5.03

- 3.85

+ 3. 19

Precession

+ 6. 18

-20.27

i

+27.20

-30.48

Refraction

+ 1.20

+ 5.60

+ 0.20

+ 5.50

Mean Zen. Dist.

the

1

08

35.87

4

50

43.65

0

12

28.65

4

43

34.44

1st Jan. 1764

Ditto Plane East

1

08

40. 17

4

50

39.71

0

12

31.98

4

43

31.79

Mean Zen. Dist.

the

1

08

38.02

4

50

41.68

0

12

30.31

4

43

33. 11

1st Jan. 1764

Ditto at Post marked West

1

08

41.80

4

50

40.40

0

12

33.00

4

43

31.20

3.78

1.28

2.69

1.91

South

South

South

South

(Average of four values) = 2"41 = 241 ft. = 3. 66 chains

That we are to the South of the true Parallel. 197

127

(Undated) Hence the offsets at every Mile Post to where the
Sector was set up, the 4th of May as follows;

Miles from the Circle from Triangle taking True offsets

Post marked West the Chord the whole length

of the Line. Then
31 Links - AT =

OP must be constantly
added.

Links

Chains

Links

Chains

Links

140. 197 miles

- 0

0

00

0

31 North

141

- 8

0

10

0

33

142

-15

0

22

0

38

143

-21

0

33

0

43

144

-25

0

45

0

51

145

-27

0

57

0

61

146

-27

0

69

0

73

147

-25

0

80

0

86

148

-22

0

92

1

01

149

-18

1

05

1

18

150

-12

1

17

1

36

Changed

) 151

- 4

1

30

1

57

the

> 151 mi. 48 ch. 0 li.

- 0

1

35

1

r k

Direction .

) 152

- 5

1

42

-12

1

53

00

t-H

1

1

65

1

78

155

-22

1

77

1

86

156

-25

1

88

1

94

157

-27

2

00

2

04

158

-27

2

12

2

16

159

-25

2

24

2

30

160

-21

2

36

2

46

161

-15

2

47

2

63

162

- 8

2

58

2

81

163

+07YTriangle

2

71

3

03

164

+ 12(LBc south

2

83

3

26

165

+24lc>f the

2

95

3

50

Sector

165. 686 miles

+32/Parailel

3

03

3

66 North 198

(Undated) Here TGP the true Parallel. ADMO the Parallel we were in at

Town Hill. Then AT = DG = OP = 31 Links.

AC LB the course run from the Town Hill. AC = CL= 11. 37 miles

Then 165.686 miles
-140.197
AB = 25.489

AL = 22.74

BL = 2. 749 = What we have over run the usual distance, at an

angle (with the chord Ld) of 8* 18" (the constant change supposing we had changed

at L to have been again in the Parallel at 10' West). Hence as Rad : BL ::

Sine 8 r 18" = Angle BLd : Bd = 53 Links. And since cd = 21 links (= the distance of the
chord from the circle at 2. 749 Miles from L) 53-21 will be = Be = 32 links - the
distance of the Parallel we were in at L.

Now 32 links = Be
+31 = OP

Sum 63 which subtract from BP - 3.66 chains (= Distance from the true Parallel found
by the Sector remains 3. 03 = co. And then as AB: Co :: AL : LM = 2. 70 chains =
the distance from the Parallel we were in at Town Hill, when we had run
22.74 Miles.

From the whole the different parts of the Triangle cLCADMo corresponding to
the intermediate miles is found (they being similar straight lines) by proportion : To
which apply the small triangle BcL*, the chord from the circle, and the constant Quantity
31 Links, that we were to the South at A; gives the true offsets from BLCA, as
by the Table.

Figure

*The right line Lc and the circle Lpc differ so little may be estimated the same. 199

128

1766

June

14 Saturday the 14th of June, 1766. Went to the top of Savage Mountain,

about 2 miles from the Tents. From hence; to the Summit of the next
Ridge called the little Meadow Mountain:

I judge by appearances to be about 5 or 6 miles: Between this, (Savage or Allegany Mts.)
and the said little Meadow Mountain, runs Savage River; which empties into
the North Branch of Potowmack: This is the most Westernmost
Waters, that runs to the Eastward in these parts.

Beyond the Dividing Mountain (Savage), the waters all run to the Westward;

The first of Note (which our Line would cross if continued) is the little Yochio
Geni, running into the Monaungahela, which falls into the Ohio or

Allegany River at Pitsbourg (about 80 miles West, and 30 or 40 North from hence) called
by the French Fort Duquesne.

The Ohio is Navigable for small craft by the accounts I have had from
many that have passed down it; and falls in to the River Mississippi

(about 36.5 degrees of North Latitude; Longitude 92 degrees from London); which empties
itself in to the Bay of Florida.

The Lands on the Monaungahela and Ohio are allowed to be

the best of any in the known parts of North America: The

Rivers abound with variety of Fish, and quantity almost incredible.

At present the Allegany Mountains is the Boundary
between the Natives and strangers; in these parts of his
Britanic Majesties Collonies.

From the solitary tops of these mountains, the Eye
gazes round with pleasure; filling the mind with
adoration to that prevading spirit that made them.

18 Set a post (18 Inches square, 3 feet in the ground and 5 above) at the
distance of 3. 66 chains. North of the Sector, marked M, on the South
Side, P on the North Side, and W on the West: and began to cut a
Visto in the true Parallel or Line between Maryland and Pennsylvania:

By drawing it through points, laid off from the Line we have run, at
every 10 chains.

19 Continued the Visto or Line, toward the Post marked West in Mr. Bryan's field,

20 Carried the Instruments to Mr. Stumblestones in Wills Creek Valley.

21 Continued the Line to the 162 Mile post.

22 Sur Went to see Fort Cumberland: It is beautifully situated on a rising

ground, close in the Northwest fork made by the falling in of Wills
Creek into Potowmack; The Fort is in bad repair; has in it at present
only 10 Six Pounders. Going to the Fort I fell into General Braddock's Road,
which he cut through the Mountains to lead the Army under his command
to the Westward in the year 1755, but fate; how hard: made through
the desert a path, himself to pass; and never; never to return.

Continued the Line. Sent three men with the Telescope
of the Sector to Captain Shelby's.

24 Continued the Line.

25 Continued the Line.

26 Continued the Line.

27 Continued the Line,

28 Continued the Line to the 154th Mile Post,

29 Sunday

30 Continued the Line,

uly

1 Continued the Line.

2 Continued the Line.

3 Continued the Line.

4 Continued the Line.

Continued the Line to the 140th Mile Post,

From the summit of Town Hill, the Visto shows itself to be the Arch of a lesser circle
of the Sphere, or Parallel of North Latitude: That part of the visto passing over the
Ragged Mountain, being apparently to the South of a right line extended to the visto
at the top of Evits Mountain.

20C

.29

1766

July

6 Sun. At Town Hill: Measured three leaves on one Stem of a Hickory,

Each of which was 17 Inches in length and 12 inches in breadth.

7 Continued the Line. This day from the Summit of Sidelong Hill I saw the Line still
formed the arch of a lesser circle very beautiful, and agreeable to the Laws of a Sphere,

8 Continued the Line.

9 Continued the Line.

10 Continued the Line.

11 Continued the Line.

Continued the Line to the 127th Mile Post,

13 Sunday

14 Continued the Line.

15 Continued the Line.

16 Continued the Line.

17 Continued the Line.

18 Continued the Line.

19 Continued the Line to the 118th Mile Post.

20 Sun. (19th, 20th and 22nd) I went to the Summit of the North

Mountain when the air was so hazy I could not see the Visto over Evit's

Mountain: But the chain carriers told me they saw it very plain on Friday the 18th;

and that the Visto over Sidelong Hill appeared to the South of a right line

(or arch of a great circle) extending to the Visto on Evit's Mountain. The quantity I

intended to have measured but was prevented for the reason above.

21 Continued the Line .

22 Continued the Line.

23 Continued the Line.

24 Continued the Line.

25 Continued the Line.

26 Continued the Line to the 107th Mile Post.

27 Sunday

28 Rain.

29 Continued the Line.

30 Continued the Line.

31 Continued the Line.

August

1 Continued the Line.

Continued the Line to the 96th Mile Post,

3 Sunday 202

Continued the Line. A great Storm of Thunder and Lightning: The
Lightning in continued streams or streaks, from the
Cloud to the ground all round us; about 5 minutes before
the hurricane of wind and Rain; the Cloud from the
Western part of the Mountain put on the most Dreadful
appearance I ever saw: It seemed to threaten an
immediate dissolution to all beneath it.

Continued the Line.

The Sun Eclipsed

Time by the Clock Time by the Clock Sun's Lower Limb

Equal altitudes of Sun's Lower Limb: Hence

m

s

h m s

o

i

the Sun's center passed the Meridian by the

7

5

16 0 47

68

16 1

mean of these two observations at 12h 3m 57s

9

42

15 58 15

69

18 /

by the clock.

7

69

50 \

47

70

30 \

56

70

57 ^

i

37

71

33-

\ Clouds prevented observing these

6

72

32.5

! corresponding altitudes

4

72

51 /

12

73

17 /

58

73

36 /

The Eclipse had not begun

Clouds during almost all

The Eclipse began within about one

the morning: and flying so

minute of this time quick we could seldom have

sight of the sun two minutes at
a time

130

1766

August

5

7

8
9

Afternoon

h

m

s

o

i

2

20

17

The Eclipse Ended

2

20

12

Ditto by Mr. Dixon

3

23

9

83

36

24

44

83

3 (

26

47

82

15. 5 ( Altitudes double.

Sim's Upper Limb

28

48

81

32 ,

4

2

35

67

31 ']

6

37

65

57.5 I

8

38

65

15 > Altitudes double

Sun's Lower Limb

9

32

64

51 \

11

39

63

56 /

4

14

58

62

45 )

18

00

61

39 i

21

15

60

26 \ Ditto for Mr. Dixon

22

46

59

41 f

24

1

59

16 \

25

33

58

41 ‘

The altitudes were taken with a Hadley's Quadrant (of 181 nch Radius) by reflection
in Quicksilver. The adjustment of the Quadrant one minute 20 seconds to be
subtracted from the observed angles: We had no Instrument with us that we
could use to find time with besides this, or any micrometer, but by appearance
the digits eclipsed were about seven*: the light was greatly diminished,
and at the middle very heavy, gloomy darkness took place.

The End of the Eclipse was observed with Reflecting Telescope
that magnified about 70 Times.

*(This evidently refers to proportion of totality.)

Time by Clock
Forenoon

h

m

s

o

i

7

53

28

60

57 \

54

44

61

28 \

56

7

61

58

57

38

62

31.5

7

59

37

63

19

8

1

11

63

56.5

3

14

64

43. 5

4

28

65

10 /

Double Altitudes of the Sun's Lower Limb

In these the adjustment of the Quadrant is one Minute and a half
to be added to the observed angles. I could wish the adjustment

of these 20 seconds were not so subject to change

These observations were made in the South-Mountain
768*yards North of the Line and 92 Miles 20 chains from the Post
marked West in Mr. Bryan's field.

* Latitude = 39° 43* 41" North

This day went to the Summit of the
Continued the Line. South Mountain, but there was

such a thick Blue mist in the Valley I
could not see the Visto to the North Mountain.

Continued the Line.

Continued the Line.

Continued the Line to the 85th Mile Post,

10 Sunday

11 Continued the Line.

12 Continued the Line.

13 Continued the Line-

14 Continued the Line.

15 Continued the Line.

16 Continued the Line to the 73rd Mile Post

17 Sunday

18 Continued the Line.

19 Continued the Line.

20 Continued the Line.

203

204

131

Eclipse of the Moon
Time by the Watch
h m s

2 55 30 in the Morning the Eclipse ended,

o i

3

13

55

31

12 \

3

16

50

30

23- > Altitudes of Alpha Lyrae taken double

3

20

40

29

15.5)

by reflection with a Hadley's Quadrant to which was applied

a Telescope that magnified about 4 times: Adjustment

of the Quadrant one minute to be added to the observed angles.

Digits eclipsed about 5, the edge of the shade was
not near so well defined as that which happened the
17th of March 1764.

These were observed about 2 Miles North of the Line and
opposite the 67th Mile Post

21 Continued the Line.

22 Continued the Line.

23 Continued the Line to the 61st Mile Post. From near this place the Visto at the top of the
South Mountain is seen; and shows the Line still forms a true Parallel of North Latitude

24 Sunday

25 Continued the Line.

26 Continued the Line.

27 Continued the Line.

28 Continued the Lane*

29 Continued the Line.

30 Continued the Line to the 44th Mile Post.

31 Sunday

September

1 Continued the Line.

2 Continued the Line.

3 Continued the Line.

4 Continued the Line.

5 Continued the Line.

6 Continued the Line to the 30th Mile Post. From the top of Slate

Ridge (at the 31 Mile Post). I saw the Visto still formed the natural Parallel.

7 Sunday

8 Continued the Line.

9 Rain.

10 Continued the Line.

11 Continued the Line.

12 Continued the Line. Sent Expresses to Annapolis, and Philadelphia to acquaint

the Gentlemen Commissioners we should finish with the Line the 27th of this Month,

13 Continued the Line to the 21st Mile Post.

14 Sunday

15 Continued the Line.

16 Rain.

17 Continued the Line.

18 Continued the Line.

19 Continued the Line.

20 Continued the Line to the 13th Mile Post

21 Sunday

22 Continued the Line.

23 Continued the Line.

24 Continued the Line.

25 Continued the Line to the intersection of the Meridian

from the Tangent point with the Parallel which finished
our Instructions.

1766

August

20

205

206

132

1766

September

25 N. B. From any Eminence in the Line where 15 or

20 Miles of the Visto can be seen (of which there are many): The said Line
or Visto, very apparently shows itself to form
a Parallel of Northern Latitude.

The Line is measured Horizontal; the Hills and Mountains measured with a 16 1/2 feet

Level and besides the Mile Posts; we have set Posts in the true Line,

marked W, on the West side, all along the Line opposite

the Stationary Points where the Sector and Transit Instrument

stood. The said Posts stand in the Middle of the

Visto; which in general is about Eight yards wide.

The number of Posts set in the West Line is 303.

26 (No entry was made)

27 Received a letter from the Gentlemen Commissioners for Pennsylvania
acquainting us, that the next meeting of the Commissioners

for both Provinces; is to be held at Christiana Bridge
in Newcastle County; the 28th of next Month.

30 Discharged all Hands

October

1 At Newark in Newcastle County

In the letter mentioned last, the Commissioners informed us,
they had no objection of our employing the interval of
time to the 28th Instant, in executing our instructions from
the Royal Society of London; towards determining the
Length of a Degree of Latitude (of which Instructions the
commissioners of both Provinces had received notice from the

Honorable: the Proprietors: To whom we wrote in June 1765 for leave to use their Instruments;
and the indulgence to do it in their Provinces.)

Accordingly from this information, we this day set out
with the Sector* etc. for the Middle Point, or South end

of the Tangent Line; To execute the following Instructions from the Royal Society.

* The Telescope part, carried by three Men.

1765

October

24 * October 24, 1765

At a (Council cof ithe Rojml -Society

Resolved that the precise measure of a degree of Latitude in

America in the neighborhood of Pennsylvania appears to the Council

and to the Astronomer Royal who was pleased to assist on this

occasion, to be a work of great use, and importance: and, that the

known abilities of Messrs. Mason ^and Dixon, the Excellence of the

Instruments with which they are furnished, the favorable level

of the Country, and their having assistants well practised in Measuring;

do all concur in giving good Ground to hope, that this

business may soon be executed with greater jprecision, itham had ever

yet been done; and at a much less charge than the Socieity can expect

an opportunity of doing it hereafter.

Resolved to employ Messrs. Mason and Dixon an the saM
admeasurement of a degree of latitude and to allow tfoeaaa the
whole of their demand, being the sum of two hundred Pounds Sterling
for the said Work: and also in case, the Proprietors of Maryland and
Pennsylvania should refuse their stipulated allowance for their
passage home, but not otherwise, the further sum of forty Pounds
for the said Passage.

Resolved that it is the sense of the Council, that Messrs. Mason
and Dixon measure the whole space required, without regarding
what they have done on a former occasion: and that they be instructed
to compare frequently their fir rods with their brass standard; and
note down the degree of the Thermometer, at each time of such

207

208

209

133

1765

October

24

comparison. also> that they take a particular" care of the brass standard;
and bring it home with them, in order to it being compared
with the french standard, if thought necessary and that the
Secretary communicate these Resolutions to Messrs. Mason and Dixon.

Resolved , that Mr. Maskelyne, Astronomer Royal, be requested
to draw up such further instructions as he thinks necessary for
Messrs. Mason and Dixon, in the work now ordered.

Resolved, that the Right Honorable Lord Baltimore and Mr. Penn
the Proprietors of Maryland and Pennsylvania, be applied to, for
the use of their instruments now there, and that C. Morton, Secretary
be desired to write to them accordingly.

Copies of the Letters from the Right Honorable Lord Baltimore and
Mr. Penn to Charles Morton Secretary.

Thursday Evening
November 7, 1765

Sir,

I beg the favor of you to present my Complements to the Council
of the Royal Society and to acquaint them that after Messrs. Mason
and Dixon have finished they are engaged to by Messrs. Penn and
Myself, I can have no sort of objection to their being otherways
employed they are extremely welcome to make use of the Instruments
already there, and I will send order to them to bring back
the Brass Rule or standard, to be compared with the french one

according to the Society's Intention. Their staying a few months 210

in America after they have finished Mr. Penn's and My Lords business
will make no alteration in the allowance Stipulated to be paid them
for their passage

I am

Sir, With great Regards

and Esteem
Your Most Obedient
humble Servant
Baltimore

Dr. Morton S. R.

Sir

I have this morning seen My Lord, Baltimore, and we both agree,

that Messrs. Mason and Dixon, after they are discharged by our

Commissioners from running the Line between Maryland and Pennsylvania,

shall be at liberty to attend the Service of the Royal Society, and

shall be allowed the same passage money, as they would

have been entitled to had they returned to England as soon as they had been

discharged by our Commissioners.

We also agree that they may make use of any Instruments belonging
to the Proprietors of Pennsylvania, provided that Lord Sterling, on the
part of the Proprietors of New Jersey, has not present occasion for
them, as the Proprietors of Pennsylvania have before promised to let
him have them. I am.

Sir

Your most humble Servant
Tho. Penn

Spring Garden, Nov. 7, 1765

Dr. MortonS. R. S. 211

134

August 8, 1766

At a Council of the Royal Society

The Council taking into Consideration the Supposed Wreck of the
Ship Egdon wherein the Instruments were sent to Messrs. Mason and
Dixon; and it appearing, that the said observers are already furnished
sufficiently for the Work ordered by the Society.

Ordered, that a copy of the instructions drawn up by Mr. Maske-
lyne, be transmitted to Messrs. Mason and Dixon, and that half an
ounce of silver wire be enclosed, therewith; and that they be directed
to proceed with their business, with the Instruments of the Proprietors
now in their hands.

Messrs. Mason and Dixon.

The enclosed are duplicates of letters sent

you from the Royal Society last year: and they

are now repeated, because your not writing

to us has occasioned a suspicion that the

former letters have miscarried. I have nothing

to add except what you will perceive,

that you are not to expect any other instruments

than what you already have: and that we

shall be glad to hear from you as soon as may be:

I am. Gentlemen.

Your most obedient, and
humble servant.

C. Morton, S. R. S, 212

Instructions sent by Mr. Maskelyne, Astronomer Royal
to Messrs. Mason and Dixon

Messrs. Mason and Dixon

Greenwich, November
8th, 1765

I have the pleasure to acquaint you that the Council of the Royal
Society, to whom I have communicated your Proposals for measuring
a degree of Latitude and a degree of Longitude, in North America,
have resolved that you should carry the first into Execution upon
the terms you offered. But to prevent any mistake, I must observe
that the Council understand your Proposals that you are to measure
all the lines over again, or at least the two principal lines, namely
the line AB, according to your Scheme which makes an angle of
4 degrees with the Meridian, and the line BC, which is due north. This
they direct should be done with four fir rods of 10 foot each, tipped with
brass at the ends, with which you will be furnished by Mr. Bird,
together with a brass standard of five foot to examine the rods
by from time to time, and one or two Thermometers to note the
temperature of the Air, whether the room or open Air, where the
rods are compared, at the time. Hence an allowance may be made
hereafter for any change the rods may Undergo. You are also desired
to bring back the rods and standard to England, as they may be
hereafter compared with the french Measures.

The Council have desired me to send you some Instructions about
the Method you should pursue in your Operations. I rely a great
deal upon your own judgment and attention, nevertheless I will
point out to you those circumstances which seem to me most
necessary you should attend to.

135

You propose setting up the sector at the point (A) the Southern extremity
of your Meridian, and observing the Zenith distances of the
same stars with it as you have already taken at (P) and (N). As you
turned the Sector at both those stations, I take it for granted you
intend to do so at (A) which I would strongly recommend to you, as it
will greatly conduce to the accuracy of the Celestial Measure.

Be very careful to trace your line strait. You might first fix stakes or

posts in the ground from distance to distance, and then stretch a long

rope by the side of them, or parallel to them as a Guide for the

direction of the rods in measuring. If the nature of the Ground is any

where very difficult, take an off sett directly at right angles, noting

how much, and go on parallel to your former course, till the

Ground allows you by another off sett or off setts to return into the

Line again. There are two Methods of measuring, either of which

may be used, or sometimes one and, sometimes the other as circumstances

vary. The one is by always laying the rods truely horizontal

by means of a carpenter's level, or Spirit level, and as the Ground

rises or falls, instead of bringing the rods to touch at the ends,

connecting them by means of a plumb line, (string silver Wire would be

best with the plummet immersed in Water) defended as much as

possible from the wind. In pursuing this Method you will find it useful

to carry stakes or Wedged pieces of wood with you to

drive into the Ground for a support of one or both ends of the

rods in levelling them. But the most convenient Method;as

well of levelling the rods as of bringing their ends to meet 214

exactly would be supporting the ends by stands which rise and

fall by a screw. It is not necessary to have a very nice spirit level for

this purpose, nor a long one, as the rods are plained strait;. I shall

send you one with the rods, which you will take care to adjust or

verify as you use it. The other method of measuring is by laying the

rods upon the ground itself, but this it is evident should only be

done where the ground is very even. In this method it will be necessary

to level the ground as you go along, to find how much it rises

and falls, in order to reduce the direct measure to a Horizontal line

and here note, that the common tables of the difference, between the

true and apparent level are very erroneous, because they take no

account of the terrestrial refraction of the rays of Light, whose curvature

near the surface of the Earth is one fifth of the curvature offthe>

Earth's Surface, on which account the numbers in all the common
tables should be diminishadun the proportion 5 to 4k.

The following expression! gives the difference of the apparent and
true level including the effteet of Refractions 0. 53^4? of the square of
the distance expressed in English Miles of SZBftifieet, ife the? difference
required in English: feefL Keep* the rods as dry as you: canv for if any
thing alters their length' it ite to* be supposed to' Use changes of
moisture and dryness, as metals; are affected by those of heat and
cold.. Always take care to> bring the' ends of the rods to meet,, without
any shock, and! don't trust this. to. your Labourers., It Will be better
to use thres rods at once, and. always leave two* on the Ground at a
time, while yon carry the third or hindfermost forward to put before
the rest, and while this rod 1 is taken up or put down let the other

rods which remain on the Ground be either held down fey the hand 21

oar pressed down fey a weight, that they may not be liable to be
moved from their place.

You will doubtless think proper to fall on some Method that may

prevent or discover mistakes in counting the number of rods laid

down* either by having several to count, or any other device usual

among Surveyors. It is very necessary and important to know with

precision the direction of your line, with respect to the Meridian (which

by the bye, is not the same at both extremities) in order to reduce it

to the distance of the Parallels of Latitude passing through the two extremities.

Though you mention that you have the direction of the Line (AB)
very exact from the time of the star in the Little Bear.next the Pole star
passing its Azimuth, yet as you have not particularly described how
you traced the Line forward in this direction, I cannot help at present
entertaining some doubts on the subject, which probably you may

112

36

hereafter clear up. However in any case I think it would be very
expedient and proper, to verify the direction of this line, which may easily
be done in the following Method.

Set up Signals at a great distance from each other as the curvature
of the earth or other obstacles will allow you to see them through the
telescope of the transit Instrument. These signals may be either
along the line or out of it, and it signifies but little how much. The
first must be observed from the South extremity of the line at (A)
and the last must be at the Northern extremity of the line at (B). The
best choice of places for the signals will be of those which will
conduct you most readily that is to say with the fewest number

from one extremity of the line to the other. If there were any hills 216

or eminences in the country, which I am afraid by the accounts

given of it, there are not, it would facilitate this business very

much, as two or three, might then carry the connection from one end

of the line to the other. With the help of the transit Instrument

determine the bearing or Azimuth of each Signal, from the preceding

one, beginning at the Southern Extremity (if convenient) till from the

last signal but one you observe the bearing of the signal, at the

Northern extremity of the line at (b). Then if the Signals lie all along the

Line AB, their bearings and known distances from each other (which

last are not required very accurate for this particular purpose) will give

the true direction of the line (AB) with respect to the Meridian though

the line traced for it and supposed a strait line be an irregular line

formed of several right lines making Angles with One another. But

if the Signals lie out of the line (AB) and their distances from the

line can be easily measured the same thing may be done as before.

But if the Signals be considerably out of the Line AB, the distances
between their parallels of Latitude may be found by setting up the
Sector at each Signal and taking a few Zenith Distances of Stars, for
great accuracy is not necessary for this purpose. The distance between
the parallels of Latitude compared with their bearings will determine
the direction of the line (AB) as before. The readiest way of finding
the bearing of any Signal from another is by directing the transit
Instrument to it, fixed and adjusted as such, and observing the interval
of time between the transits of two known stars across its vertical, one
of which shall be as near to, and the other as far from the pole as
possible. If your clock is good and its rate of going well determined,

it is immaterial whether the Interval of time between the transits 217

of the two stars over the given vertical be great or small.

As I do not find that you have a clock with you, I shall make a
proposal to the Council of the Royal Society, that their clock, which I
took to St. Helena and Barbados may be sent to you, with the help
of which joined to your transit Instrument you may determine the
bearings of your Signals many different ways, and make any other
Astronomical observations. Always fix the clock up firm, and adjust
the pendulum to the same length, and it will always keep the same rate
of going very nearly. If the interval of the transits of the two Stars is
small, it is not necessary to be so very nice about the rate of the clocks
going. Should this clock be sent to you adjust the Pendulum to the
Upper Scratch No. 3 standing against the Index which answered to
Sidereal time at St. Helena, and keep the clock going in the same place
for some days, in order to determine its rate of going. Note the height
of the thermometer at the time. Th is Experiment will show the force
of Gravity, where you set it up, compared with the force of Gravity here.

At Saint Helena, the Cape of Good Hope and Barbados. Endeavor to
Estimate your Elevation above and distance from the Sea where you
set the clock up, also note the Latitude of the place.

You ought to determine the direction of your line within five minutes, and
the whole length within the ten thousandth part of the whole or fifty
feet.

Preserve all your Measures and Observations as they may be revised
At leisure. I am etc.

N. Maskelyne, Astronomer Royal 218

137

To Messrs. Mason and Dixon in Pennsylvania

Instructions for Measuring a degree of Latitude

there. 219

Sorjts Inn London 22 March 1766

Gentlemen:

By tne death of Mr. Calvert it falls to my lot to
acknowledge the receipt of your letter of SLdih of January last, addressed to
him which I have communicated to Lord Baltimore, and his Lordship
has directed me to express his satisfaction in your Proceedings, and the
happy prospect of bringing your great work to a conclusion in the
ensuing summer.

His Lordship, from a due Sense of your Services, and a
desire of showing his approbation of them has in concurrence with
Messrs. Penn agreed to your Entering upon the Important charge
Proposed to be Delegated to you by the Royal Society, as soon
as the business of his commission is ended and to Indulge you the use
of the Instruments for that Work, with a Continuance of the same
Allowance for your return as was first agreed, in the same manner
as if you had engaged in no new Undertaking.

When you renew your Operations I shall be glad to be
favored with accounts of your further Proceedings, as opportunities
offer, and in the meantime remain

Gentlemen

Your most Obedient and Humble Servant
Hugh Homersley

Messrs. Charles Mason and Jeremiah Dixon 220

Gentlemen

We are to inform you that the Time of our
Meeting the Maryland Commissioners has been postponed by our
mutual agreement to the Twenty Eighth of the next Month.

You will therefore discharge your Workmen as soon as you
Return to the East End of the East and West Lines. If you think
the Season is proper for you to measure a Degree of Latitude
agreeable to your Instructions from the Royal Society, we have
no objections to your employing yourselves in that Business
till the time of our Meeting, but we shall then expect you will
attend us at Christiana Bridge in New Castle County to lay
your Books before us and make report of your Work. We are

Gentlemen

Your humble Servants

Will Allen
Benjamin Chew
John Ewing

Philadelphia, September 19th, 1766

P. S, I had sealed the Letter before I had

filled up a Blank left at first Writing for
the Day of our Meeting which obliged me
to break it open again.

B. C,

138

(Undated-

(Undated.

«Here we have an envelope addressed as follows
and to which other comments are annexed as shown.)

To Messrs

Charles Mason & Jeremiah Dixon
New Castle County

(On back) This letter was broke open and resealed by me;.
B. Chew

(Also on back at end) Betsy Little

Opposite the Butanes
Philadelphia

Messrs. Mason and Dixon:

1- nave received your letter of the 6th of January
with a particular account of your proceedings, since your last, and we
are very well satisfied with the account you give of them; We apprehend that
you cannot have put stones to every Mile of the Line from Cape Henlopen to
the Middle of the Peninsula, or in the'Tangent Line, unless you had many
made in Pennsylvania, the particular place you have noted down where
the parallel of Latitude has crossed, we are very well pleased with; as we
are that you made use of your time when not employed by us to run the
Degree of Latitude for the Royal Society about which my Lord Morton often
Speaks to me.

I am at a loss to know what was the Commissioners reason for ordering
you to run the parallel of Latitude from the place where the Meridian Line
intersects it to the River, as I have not received from them their minutes, and
when you write next let me know them lest they should omit it.

I shall expect to hear from you if you proceed to extend the Line
further westward in the mean time remain.

London, June 17, 1767

Your affectionate Friend
Tho. Penn

Editorial Note:

Here is an envelope addressed as follows)
For

Messrs. Mason & Dixon
in Pennsylvania

(On the back of the envelope is the following notation)

To the care of John Montgomery, Esq. at Carlisle,
who is devised to put this Letter under a Cover and to
forward it by the first opportunity to Fort Cumberland
or wheresoever Mr. Mason or Mi. Dixon may be.

Joseph Shippen, Jr.

222

223

224

139

1766

October

8

9

10

Set up the Sector at the Middle Point (in a West
Line) between Cape Henlopen and Chesapeak Bay: and
made the following observations.

Plane of the Sector EAST

Star Name

Nearest Point

Revolutions

Difference

Apparent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

n

t

II

o

i

ii

Gamma Andromedae

2

45-

5

31-

0

31.3

2

44

28. 17

6

10

Beta Persei

1

35-

7

8

0

6.0

1

34

7

14

Delta Persei

8

35-

7

32+

1

25.0

8

33

35.0

9

13+

Cape 11a

7

15+

6

16

1

21.3

7

16

21.3

4

39-

Beta Aurigae

6

25+

3

34-

1

3.2

6

26

03. 2

2

22.5

Castor

6

05-

1

10

0

9.5

6

04

50.5

1

0.5

Cloudy

Alpha Lyrae

0

05+

3

26.5

2

19.0

0

7

19.0 N

0

43.5

Gamma Cygni

1

05-

4

42

1

7.7

1

3

52.3 N

6

6-

Alpha Cygni

6

00-

5

41

0

4.7

5

59

55.3 N

5

46-

Gamma Andromedae

2

45-

7

12

0

30.0

2

44

30.0 N

7

42

Beta Persei

1

35-

8

15. 5

0

06.5

1

34

53. 3 N

8

22

Delta Persei

8

35-

5

51.5

1

25.5

8

33

34. 5 N

7

33

Cape 11a

7

15+

6

48.5

1

20.0

7

16

20.0 N

5

20.5

Beta Aurigae

6

25+

3

29. 5

1

4. 0

6

26

4.9 N

2

17.5

Castor

6

05-

15

25

0

9.5

6

04

50.5 S

15

15.5

225

Alpha Lyrae

0

5+

8

26

2

20.7

0

7

20.7

5

41

Delta Cygni

6

5+

5

44-

1

51.0

6

6

51. 0 N

3

37-

Gamma Cygni

1

5-

3

37

1

8.0

1

3

52.0

5

1

Alpha Cygni

6

0+

4

32

0

5.5

6

0

5.5

4

37.5

Gamma Andromedae

2

45-

6

14-

0

29.3

2

44

6

43

Beta Persei

1

35-

7

42-

0

4.3

1

34

7

46

Delta Persei

8

35-

5

38. 5

1

23.0

8

33

7

17.5

Cape 11a

7

15+

8

51

1

20.3

7

16

20.3

7

23-

Beta Aurigae

6

25+

7

20.5

1

4.0

6

26

6

8. 5

(Castor

6

5-

4

31

0

10.5

6

4

140

1766

October

Star Name

Nearest Point

Revolutions

Difference

ADDarent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

n

t

II

o

Alpha Lyrae

0

5+

5

29-

2

22.0

0

2

43-

Delta Cygni

6

5+

4

31.5

1

51. 0

6

6

2

24. 5

Gamma Cygni

1

5-

6

26

1

9.0

3

51. 0

7

43

Alpha Cygni

6

0+

13

8

0

3.5

6

0

3. 5

13

11.5

Gamma Andromedae

2

45-

2

37+

0

32.4

2

44

3

18-

Beta Persei

1

35-

3

46

0

5. 0

1

34

55. 0

3

51

Delta Persei

8

35-

1

43

1

27. 0

8

33

3

26

Capella

7

15+

6

28

1

22. 0

7

16

4

50

Beta Aurigae

6

25+

1

33+

1

4. 0

6

26

0

21+

Castor

6

5-

15

37.5

0

8.0

6

04

15

29. 5

Turned the

Sector Plane WEST

Gamma Andromedae

2

45-

6

2+

0

24. 8

2

44

5

29.5

Beta Persei

1

35+

5

43

0

0.7

35

5

44-

Delta Persei

8

35-

6

2.5

1

22. 5

8

33

4

24

Capella

7

15+

7

4,5

1

27. 5

7

16

8

40

Alpha Lyrae

0

5+

* 14

12

2

21. 0

0

7

16

49

Alpha Cygni

6

00

13

16

0

00.0

6

0

00.0

13

16

Gamma Andromedae

2

45-

2

46

0

24.0

2

44

36. 0

2

22

Beta Persei

1

35+

2

5-

0

0.6

1

35

0.6

2

5+

Delta Persei

8

35-

3

27+

1

19. 6

8

33

2

0-

Capella

7

15+

1

50+

1

29. 7

7

16

3

36

Beta Aurigae

6

25+

2

51

1

11. 5

6

26

11. 5

4

18.5

Castor

€

05-

7

17

0

12. 0

6

04

48.0

7

29

Wound up the clock; in which it was stopped about 23 seconds.

226

141

1*66

October

15

16

17

18

Star Name

Nearest Point

Revolutions

Difference

ADDarent

on the

Sector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

H

i

II

o

Alpha Lyrae

0

5+

3

33

2

22. 7

0

07

22.7

6

20-

Delta Cygni

6

5+

6

18

1

58.0

6

06

58.0

8

32

Gamma Cygni

1

5-

7

4

1

5.3

1

03

54. 7

5

43-

Alpha Cygni

6

0+

6

36+

0

1. 2

6

00

1. 2

6

37.5

Gamma Andromedae

2

45-

6

40.5

0

24.5

2

44

35. 5

6

16

Beta Persei

1

35

5

48-

0

0.0

1

35

0.0

5

48-

Delta Persei

8

35-

8

2

1

22.0

8

33

38. 0

6

24

Capella

7

15+

7

21.5

1

27.5

7

16

27. 5

9

5

Beta Aurigae

6

25+

9

25-

11.8

6

26

11. 8

10

44.5

Castor

6

5-

12

45+

0

12. 7

6

4

47.3

13

6

Alpha Lyrae

0

5+

4

48+

2

22.7

0

07

22.7

7

35

Delta Cygni

6

5+

2

20.5

1

55. 2

6

06

55.2

4

32-

Gamma Cygni

1

5-

0

25

1

4. 5

17

12. 5

Alpha Cygni

6

0+

0

8.5

0

0.5

6

0

9

Gamma Andromedae

2

45-

4

31. 5

0

28.0

2

44

32. 0

4

3.5

Beta Persei

35

3

25

0

0.0

1

35

0.0

3

25

Delta Persei

8

35-

4

4

1

23. 5

8

33

36. 5

2

24. 5

Capella

7

15+

1

20-

1

29. 3

7

16

29.3

3

5

Beta Aurigae

6

25+

5

29. 5

1

10.5

6

26

10.5

6

48

Castor

6

5-

8

5

0

10. 5

6

04

49. 5

8

15. 5

Alpha Lyrae

0

5+

5

18-

2

23.3

0

07

23.3

8

5

Gamma Cygni

1

5-

8

1. 5

1

04.0

1

03

56. 0

6

41. 5

Alpha Cygni

6

0-

6

48. 5

0

0.5

5

59

59.5

6

48

C ape 11a

7

15+

8

43

1

27. 5

7

16

27.5

10

26.5

Beta Aurigae

6

25+

10

39-

1

11. 3

6

26

11.3

12

0.6

Castor

6

5-

12

14-

0

11.6

6

04

48.4

12

25+

Alpha Lyrae

0

5+

6

49

2

25.3

0

7

25.3

9

38+

Delta Cygni

6

5+

7

45-

1

59.3

6

6

59.3

10

0. 8

Gamma Cygni

1

5-

5

15

1

04.0

1

3

56.0

4

0.3

Alpha Cygni

6

00+

16

47-

0

2. 3

6

0

2. 3

16

49

142

1766

October

12

11

12 Sun.

Observations made at the Middle Point for determining the Angle of our 1st Line
with the Meridian, etc.

Apparent Right Ascension of Stars the 12th October 1766
O * *» h m s

308

22

33

222

53

30

161

54

9

162

16

54

175

22

47

359

5

32

180

56

17

190

55

4

11

29

49

198

36

47

Time by the Clock

h

m

s

18

31

17. 5

20

16

10

20

25

40

19

51

27

52

49-

54

13

22

18

59

22

22

34

23

34

19+

h

20

14

10

10

11

23

12

12

0

13

m

33

51

47

49

41

56

3

43

45

14

s

30
34
37

8

31
22
45
40
59.5
27

Alpha Cygni

Beta Ursae Minoris

Beta Ursae Majoris

Alpha Ursae Majoris

Gamma Ursae Majoris

Alpha Andromedae

Delta Ursae Majoris

Epsilon Ursae Majoris (Alioth)

Polaris

Epsilon Ursae Majoris
These reduced by both hands

h

m

s

2

51

34 \

22

47

37 >

22

49

08

23

41

31 1

i

0

3

j

45

0

43

40

12

45

59.5

1

14

27 1

Under the
Pole

Alpha Lyrae 1
Gamma Cygni >

Passed the Meridian by the Sector

h

21

Alpha

Cygni ;

m

s

h

m

s

h

m

s

17

10+

41

11

23

20

35

41. 5

18

35+

11

24

35

42 :

19

56

11

23

41. 5

Equal Altitudes of Alpha Cygni

2 Oh
2 Oh

35m

33m

42s

30s

2m 12s

Alpha Ursae Majoris passed our 1st Line: upper star
Beta Ursae Majoris passed our 1st Line: lower star
0

Clock too fast for sidereal time

18

14

47

57

31

29

58

45. 5 )

20

54

57

31

23

58

45. 5

> Equal Altitudes of Alpha

23

13

57

32

18

46 )

1 Andromedae

23

58

46

23

56

22

Right Ascension

2m

24&

Clock too fast

18

32

23

20

17

13

20

36

45-

22

20

13

Alpha Ursae Ma

23

26

Beta Ursae Maj'

20

0

16

21 10 22

1

42

11 47-

3

15

13 14

Alpha Lyrae \

Gamma Cygni l Passed the Meridian by the Sector
Alpha Cygni j

ris passed our 1st Line: upper §tar
is passed our 1st Line: lower star

41

41

13

13

29-

30

20

36

36

%

Iqual Altitudes of Alpha Cygni

44.

_ 45

20 36 45- Passed according to the clock

20 33 _30 = Right Ascension

3m 15s-Clock fast 229

143

1766

October

Time by the Clock

Sum

Half-Sum

h m

s h

m

s

h m

s

h

m

s

19 50

41 21

22

12+

41 15

33

20

37

46.51

51

58

23

35.5

15

33.5

37

47- > Equal Altitudes of Alpha Cygni

53

20.5

24

52

15

33

37

46.5)

20

37

46. 5 Passed the Meridian by the Clock

20

33

30.0 Right Ascension

4 16. 5 Clock too fast

22 21 16 Alpha Ursae Majoris passed our 1st Line

22 24 21 Beta Ursae Majoris passed our 1st Line

Hence by Alpha Cygni the Clock gains 61.5 seconds per day (of Sidereal Time), then
22 49 8

+4 16. 5

+ 0 5+

22 53 30 = The time’ by the clock when Alpha Ursae Majoris will pass the Meridian under the Pole

23 41 31

+4 1G, 5

tO B

Z3 t5 5b. !i - The Tinm the Clock when Gamma Ursae Major Will pass the Meridian under the Pole

0 46 00

4 16

_ 0 11

0 50 27 « The Time when the Pole Star will be on the Meridian: and at the Instant

when the Clock showed 22h 53m 30s, the vertical wire in the Equal Altitude Instru¬
ment was brought to bisect the star Alpha Ursae Majoris and there made fast.

(The Level showing the Horizontal Position of the Axis of the Telescope: and the
Line of Collimation in the Evening made good). The Telescope was then brought
parallel to the Horizon and by a candle through a small hole, a mark at the dis¬
tance of 21 chains was placed opposite the above mentioned wire as a meridian: Northwards
at the Distance of 21.42 Chains. When Gamma Ursae Majoris, and the Pole Star passed according
to the Clock, they were both run down to the Horizon in the same manner, and the wire
Bisected the 1st Mark as near as could be judged. 230

14 Time by the Clock

h

m

s

h

m

s

h

m

s

h

m

s

20

2

21

21

12

15

41

17

35

20

38

47.51

3

48

13

47

17

35

38

47 .5 fequal Altitudes Alpha Cygni

5

20+

15

14

17

35+

38

47.5)

20“"

38

47.5,

20

33

30

17. 5 Clock fast

23

37

44. 5

0

20

49

0

3

36

0

1

48 1

40

06. 5

23

32

3

38. 5

1

49+/ Equal Altitudes of Alpha

42

47

25

54

3

38.5

1

49+) Andromedae

0 1 49-

23 56 22

5 27- Clock fast

Hence

0

45

59.5

+ 5

17.5

+ 0

13

~Q~

51

30

Time by the Clock when the Pole Star will be on the Meridian *

2

51

34

Right Ascension Beta Ursae Minoris .

+ 5

17. 5

~

+ 0

19

57

10. 5

Time by the Clock when Beta Ursae Minoris will be on the Meridian

At

2

3

40

Beta Ursae Minoris passed our 1st Line.

Cloudy when the Pole Star passed the Meridian,

At

2

47

10.5

Ran down Beta*Ursae Minoris for a Meridian, and by a

Candle at the distance of a mile, being brought opposite
the vertical wire we there placed a Mark. After these Observations, wound up the
Clock, in doing which it was stopped about 23 seconds.

144

1766

October

15

16

h

ip

22

m

52

53

54

31

s

14+

32.5

55.5

56

h

21

Sum

m

s

h

m

s

h

m

23

47

41

18

42.5

20

39

25

10

18

42. 5

39

26

28

18

42+

39

20

20

Delta Ursae Minoris passed our 1st Line,

Allowing the Clock to go as before then

45
+ 5
+ 0

s

21+1

21+ /Equal Altitudes Alpha Cygni

21 )

21 +

30

Clock too fast

59.5)

51 \

13 )

0 52 3.5 Pole Star on the Meridian

At Oh 52m 3. 5s the Pole Star was Observed for a Meridian. It was rendered dubious
by Clouds, but a mark was placed at the distance of .a mile, and it fell 5 inches
East of the mark placed by Beta Ursae Minoris last night.

Ursae Minoris passed 1st Line.

At 2h 4m 18s Beta

231

Time by the Clock

h

20

22

22

22

23

m

0

1

3

23

26

32

41

43

46

s

17

41

8

46

45.

45

16

51. 5
51

h

21

m

17

18
20

24

51.

16

h

41

Sum

m

20

20

20

32

32. 5

33

Half-Sum
h m
20 40

40
40

s

16

16+

16

:r

[ual Altitudes of Alpha Cygni

20 40 16+

20 33 30

6 46+ Clock too fast

Alpha Ursae Majoris passed our 1st Line*

Beta Ursae Majoris passed our 1st Line.

Delta Ursae Minoris passed our first Line. This is the Star whose
passage over the Line is so often taken in 1764.

19

22

25

46

46

22

37

37.5

38

18.5)

19- /Equal Altitudes of
19 ) Alpha Andromedae

0

23

3

56

19-

22

6 57- Clock too fast. Hence by

the going of the clock in the interval between Alpha Cygni and Alpha Andromedae
passing the Meridian we have

and

At

0

53

00

At

2

5

10

At

2

58

41

0

45
+ 6
+ 0

59

46

14

0

53

00 =

2

51

34

+ 6

46

+ 0

21

2

58

41 -

00 = Time when by the Clock the Pole Star will be on the Meridian

41 = Time when Beta Ursae Minoris will be on the Meridian.

Brought the wire to the Pole Star as usual, and by the Candle at the
distance of a Mile, placed a mark, which fell as near as could be
judged on the Mark placed the 14th.

Beta Ursae Minoris passed our 1st Line.

Brought the wire to Ditto for a Meridian as before, and by a

Candle at the distance of a Mile placed a mark, which fell three inches East

of that placed 14th. In this last Observation I turned the axis of

the Telescope end for end; that is the Telescope itself was turned

upside down: This proved the Ends of the Cylinders to be good.

232

145

1766

October

17 In the Evening by a Candle placed behind a board with a small hole in it, right

over the Mark placed the 13th, the line was extended to the marks at a Mile Distance
and there a Mark was placed which fell one-fourth of an Inch East of the Mark placed
the 14th.

From the whole there is 6 Observations all within three Inches at the distance of a
Mile; The mean was taken as a point in the Meridian from the Middle Point: over
which said Middle Point, the Axis of the Equal Altitude instrument was placed when
the Observations were made.

At the above Meridian Point, we laid off a Line (pg) at Right Angles, and by a Candle
being placed at the distance of about a mile and a quarter in our 1st Line over a
Notch in a peg left in our 1st Line in the ground; another Candle was brought in
to the 1st Line, Under which a mark was set at the intersection of the Line at right
Angles with the meridian and our 1st Line.

18 The ground being made smooth (level as a floor by nature) the distance was measured
(twice) between the Meridian Point, and the above 1st Intersection in our 1st Line,
and found to be five Chains 14 feet and three tenths of an Inch.

With this same Chain (made by a Brass Statute Yard) the distance from the above
mentioned Meridian Point, to the Middle Point was measured, and found exactly 80
chains. This had been measured several times before in the year 1760; when a
North Line was run from the Middle Point: and their Meridian Mile Post; is nine

feet and 10 Inches East of ours. 233

Observations for determining the Moon's Right Ascension made at the Middle Point
or the South End of the Tangent Line.

Method: Over the Point in the Meridian at the distance of a mile north a Candle was

placed: to which the vertical wire in the Equal Altitude Instrument was brought
and in that position the vertical axis of the said instrument was made fast;

Then the Telescope was turned to the Southward; and the passage of the Moon and
Star taken: Always just before, and after each observation turning the Telescope
to the North to see that the wire still bisected the Candle.

N. B. Time would not admit of our cutting a Visto, and placing a Mark in the Meridian
Southward.

17 Time by the Clock

h

m

s

h m

s

23

40

40

43

04

0 25

27

Equal Altitudes of Alpha Andromedae

45

51

27

50

Hence passed at Oh 4m 15s

Right Ascension of Star 23h 56m 22s

Clock too fast 7m 53s+

36

32

1st Wire

37

23

Meridian

The Moon's first or Western Limb passed the Meridian.

38

15

3rd Wire

38

50

1st Wire

39

41. 5

Moon's last or Eastern Limb passed the Meridian.

40

34

1

49

46. 5

Beta Arietis passed the Meridian: a Star about 3 or 4° N of Moon

2

02

02

Alpha Arietis passed the Meridian: a Star about 8P N of Moon

4

30

39-

Aldebaran passed the Meridian:

4

48

10

49

23. 5

5 51

42 I

Equal Altitudes of Beta Aurigae

50

42

52

56/

234

146

1766

October

18

19 Sun.

Time

by

the Clock

h

m

s

h

m

s

23

48

52

0

12

56

52

22

18

4

57

27

21

33.5

2

35

47

1st wire

36

40

37

33

3rd wire

6

18

12

7

9

40

23

26

17.5

0

42

34)

27

52

44

18 \

29

35

45

52 )

34

35

36

40

41

41

42

43
45
45

32

13

36

3«

52

32. 5
28
22

54

12

50

22

30

11

26

15

56.5

48+

48

> Equ

.5)

.iL A ] t l Lu i_-£ of Alpha Andromedae

Mr. Dixon.

1st wire
3rd wire

Moon "a Eastern Limb passed the Meridian
Equal Altitudes of Ssriua

Equal Altitudes of Alpha Andromedae

Alpha Arietis passed the Meridian (the upper star mentioned 17th)
Moon's Eastern Limb passed the Meridian

\

The brightest star Eta Pleiades (TaurO/

Stars in the Pleiades passed the Meridian.

Aldebaran passed the Meridian.
Rigel passed the Meridian.

Sum

Or a Star

27

33.5

13 8

21. 5

by itself

29

34

8

22 |

Equal Altitudes of Gamma Geminorum

about 25°

31

26

8

22.5 (

Zenith

6 34

n ;

This Star passed by the clock

Distance

When Twilight began I saw (with a small Reflector) some of the Stars in the Pleiades
very near the Moon's Limb.

South

N. B. The three wires in the Telescope of the Equal Altitude Instrument have not

been proved to be of equal distance from each other; Though they seem to be

very nearly so. 235

20 Packing up the Instruments-

21 Left the Middle Point.

24 At Newark.

26 The Waggon; and three men with the Telescope part of the Sector arrived at Newark .

27 Examined the Instruments and found that they had not received any damage.

28 At Christiana Bridge in Newcastle County.

29 One of the Commissioners for Pennsylvania came to the Christiana Bridge in Newcastle
County and acquainted us, the Gentlemen Commissioners were not to meet at this Time;

And that we were to proceed immediately to set 100 Stones (one at each mile) in the
Line.

November

17 The Gentlemen Commissioners of both Provinces met at Christiana Bridge.

Attended the meeting of the Gentlemen Commissioners of both Provinces at Christiana
Bridge.

Attended the meeting of the Gentlemen Commissioners of both Provinces at Christiana
Bridge.

20 Attended the meeting of the Gentlemen Commissioners of both Provinces at Christiana

Bridge. The Stones all Set; which finished the Tangent Line: from the Tangent Point
to the West Line: and 65 Miles of the said West Line, or Boundary between Maryland and
Pennsylvania, the 64th Mile from the beginning of the West Line excepted, at which
there is no Stone.

One of the Gentlemen Commissioners of each Province attended this work. 236

147

1766

November

20

21

22 )

23 Sun. *

24 )

25

N. B. The Stones in the West Line are Set 73 Links Eastward of the Mile Posts; so
that they stand at even Miles from the North-East end of the Province of
Maryland, or the Beginning of the West Line.

Attended the Gentlemen Commissioners.

At this Meeting the Commissioners agreed we should immediately proceed to extend the
West Line (from the Post Marked West in Mr. Bryan's field) Eastward to the River
Delaware. And also Resolved that General Johnson (his Majesty's Agent for Indian
Affairs) should be applied to (if they will not sell their Land) for to gain the
consent of the Six Nations to let us continue the West Line to the extent of the Provinces.

Preparing a Post for the Transit (or equal altitude) instrument; Boards for Mark,
finding a Point in the west line, etc.

Changed the Direction found by Stars on the 20th of March and 4th of April 1765; to
be in the true Parallel of the West Line, at the distance of 12 Miles 25 Chains
Eastward of the Post marked West in Bryan's field. Thus: if we had run WB,
the true chord*, then9' 00" is the Angle for a Chord of 12 miles 25 chains which
being changed would give the true chord WE for 12 miles 25 chains the direction:

But as we found on setting up the Sector at S we were 1 chain 95. 5 links north of the

parallel the changing of 9' 00" only; will carry us to N, making NE « BS = 1 Chain 95. 5

Links. To account for which: As 12 Miles 25 Chains : 1 Chain 95 Links :: 0. 5 Mile : 7. 92 Links to the

error in . 5 mile. And at 0. 5 Mile Rad 9' 00" 10. 5 Links

Sum to be laid off from WS southward, that is from a to c at a 18.42 Links

Radius of 0. 5 Mile in order to run the true chord WE Eastward

26

27

29

We measured a Radius Westward from W to a = 45. 5 Chains, and laid off from a to c
20. 16 links and in this direction cWE (W being the Post Marked West) we ran East¬
ward for the Delaware as follows.

* When we set out on April 5th 1765 to run the West Line.

At 0 miles 23 chains Mr. Culbertson's House about one chain North.

1 mile 06 chains crossed a road leading from Christiana Bridge toward new Garden
Meeti ng House.

Continued the Line: At 1 mile 64 chains crossed Pike Creek.

Continued the Line,

At 3 miles 42 chains crossed Mill Creek.

At 4 miles 02 chains crossed a Road leading from Newport to Lancaster.

At 5 miles 24 chains crossed Red Clay Creek.

At 5 miles 68 chains crossed a Road leading from Newport to Lancaster.

Continued the Line.

At 6. 5 miles Newport Bore south: distant one-half mile.

At 7 miles 27 chains crossed a Road leading from Newport to Willingstown, or Wilmington
Continued the Line. At 9 miles 7 chains 17 links the West Bank of Christiana Creek.
Measured the breadth of the Creek thus

Figure

237

B a point pn the East Bank.

A a point on the West Bank.

AC a base at nearly right angles to the Line AB = 6 Chains;
the angles as by Trigonometry measured with a Hadley's Quadrant
(log)

As Sine B (25° 17') = 9. 630524

: Ac or 6 * 0.778151

:: Sine C (61° 51') = 9,945328

AB 12 chains 38 links - 1.092955

at A 9 miles 7 chains 17 links

9 miles 19 chains 55 links = the measure at B

At 9 miles 79 chains crossed a Road leading from Newcastle to the Lower Ferry on
Christiana Creek.

30 Sun. Placed a Mark in the Line on the Bank of the Delaware.

Measured Christiana Creek a second time, in the direction of the Line thus.

Figure

238

148

1766

November
30 Sun.

Thus BC a Base on the East Side of the Creek = 13 Chains 55 Links. AC the Line.

A, a point on the West Side, and B, a point on the East Side. The Angles Measured
as by Trigonometry: then 81° 33» + 45° 3» = 126© 36' complement = 530 24' = the angle A

As sine A 53° 24'
: AB 13° 55'

: : Sine B 81° 33'

AC 16 chains 69. 5 links

(log)

9.904617
1. 131939
9.995260
11. 127199
9.906617
1.222582

Note: There we passed the
creek very oblique.

December

1

10 miles 52 chains 87 links = the measure at A,

10 miles 69 chains 56 links = the measure at C, on the east side of the creek.

At 10 miles 52 chains 87 links the west bank of Christiana Creek the second time.

11 miles 11 chains The North Side of a House belonging to Mr. Wm. Pewsey is
south 2 chains 10 links.

11 miles 14 chains The most southernmost part of a Marsh called Cherry Island;
is South, three chains and 57 links.

At 11 miles 20 chains 88 links, the top of the Bank of the River Delaware.

This distance falling short of 12 miles 25 chains by 1 mile 4 chains 12 links the
true Parallel is Seven feet South of the Line or Mark placed on the Bank of the
Delaware yesterday.

Placed a post (marked E, on the east side) on the Bank of the River Delaware in the
Parallel of 15 statute Miles South of the Southernmost Point of the City of Phila¬
delphia.

This Post is distant from the Post marked West in Mr. Bryan's field 11 miles 20
chains 88 links; And at the time of Setting the said Post; the water of the Delaware
was nearly five feet to the eastward.

From the Post marked E on nearly a South Course (south course a little Westerly)
to a Corner of a Marsh in which it stands, is one chain 80 links: This Corner and
its opposite Land to the Southward we judge to be the Mouth of Christiana Creek.

The said post marked E stands on the Bank of a marsh belonging to Mr. Wm. Pewsey
of Philadelphia, very near the Southernmost part of Cherry Island.

N. B. We set Posts in the Line (marked E, on the East Side, with the number of Miles)
at the End of each Mile, from the Post marked West in Mr. Bryan's field.

1767

January

6 Wrote to the Honorable Proprietors of Maryland, and Pennsylvania.

Wrote also to the Reverend Nevil Maskelyne, Regius Professor of Astronomy; and
Dr. Morton, Secretary of the Royal Society.

Figure

93Q

240

1766

December

2 \ At Newport, Snow fell all these two days,

3 /

4 Left Newport.

5 At Brandywine.

H The Sector set up at Mr. Harland’s in the same Parallel that it stood in, in the year

1764 and made the following Observations.

Here we also set up the clock, sent us by the Royal Society of London: and also
the Proprietors Clock, to which I applied a Pendulum made with Walnut that had
lain dry for about 40 years.

149

1766

December

13

14 Sun.

15

16

Star Name

Nearest Point Revolutions and

on the Sector Seconds on the

Micrometer

Difference Apparent

Zenith Distance

o

i

R

H

Gamma Andromedae

1

15+

5

20.5

0

54. 8

1

15

54. 8

4

18-

Beta Persei

0

5+

4

46+

1

20.3

0

6

20.3

3

18

Delta Persei

7

5+

4

8

0

2.0

7

5

2.0

4

6

Cape 11a

5

50-

5

35

2

18.0

5

47

42.0

8

17

Cloudy

Gamma Andromedae

1

15+

7

32

0

55. 0

1

15

55. 0

6

29

Beta Persei

0

5+

8

3-

1

21. 7

0

6

21.7

6

25

Delta Persei

7

5+

6

27

0

3.0

7

5

3.0

6

24

Capella

5

50-

4

46. 5

2

19.0

5

47

41.0

7

29.5

Beta Aurigae

4

55+

9

20.5

2

27.0

4

57

27.0

6

29.5

Castor

7

35-

9

14.5

1

23. 5

7

33

36.5

7

35

At 2h

53m 56s

Star passed the meridian

by the Sector:

Beta Persei

Note: This day we set the Pendulum of the Royal Society's Clock to the upper

scratch with Number 3

at the index as desired

by Mr. Maskelyne.

Gamma Andromedae

1

15+

9

37-

0

55.7

1

15

55.7

8

33

Beta Persei

0

5+

7

45.5

1

21. 0

0

6

21. 0

6

16. 5

Delta Persei

7

5+

5

21. 5

0

2.0

7

5

2.0

5

19.5

Capella

5

50-

7

11

2

18.7

5

47

41.3

9

46-

Beta Aurigae

4

55+

9

39

2

27.7

4

57

27.7

6

47+

Castor

7

35-

6

34. 5

1

21. 8

7

33

38. 2

5 5-

2h 50m 40s Passed the Meridian by the Sector, Beta Persei

4h 50m 37s 6° 32' 34 , . , 5

4 51 50 33' 52" Equal altitudes of Beta Aurigae by the Royal Society's

53 8 35' 5" Clock which I call P.

11 26 00 The first S atellite of Jupiter I mmerged. Fahrenheit Thermometer, in

the Tent 14°, in the Air 10°. This Day the Proprietor's Clock was cleaned by the
maker, Mr. Jackson; which clock I call Q.

17

Alpha Lyrae

1

20+

5

44-

1

42.0

1

21

42.0

Cloudy all the day after

7

42-

18

Cloudy

19

Alpha Lyrae

1

20+

5

1. 5

1

43. 5

1

21

43. 5

1

Windy

Beta Persei

0

5+

8

42.5

1

20.2

0

6

20.2

14+

Delta Persei

7

5+

7

4

0

3.7

7

5

3.7

7

0+

Capella

5

50-

5

42.5

2

16.0

5

47

44. 0

8

22

Beta Aurigae

4

55+

8

. 6+

2

27.3

4

57

27.3

5

15

Castor

4

45+

1

21. 3

7

33

38.7

3

16

20

Cloudy

21

Alpha Lyrae

1

20+

3

2

1

41. 7

21

41.7

0-

24

150

1766

December
21 Sun.

22

23

Turned the Sector rio.Hr WEST

Dry fair
weather

Star Name

Nearest Point

Sievolulions

Differ once

Apparent

on the Sector

and SecamEr* on

Zrtmlli Distance

ihc Micrometer

c

r

R

H

ii

4

r

AL 22h 20m p before Q lm 22s

Beta Persei

0

5+

6

4+

]

29.7

□

ft

29,

7

42

Delta Persei

7

5+

7

50-

0

10. 3

7

5

10* 3

B

s

Capella

5

45*

4

5“

2

55, a

5

47

&&. d

7

35,5

5

□0-

4

5-

2

07+ Si

5

47

52 P H

1

33. 5

Bela Aurigpe

4

551

7

O-

2

35.3

4

&7

35.3

3

51

Castor

7

35-

10

0+

1

3Q< 0

7

33

3D. 0

U

3 0r

At Sli 49m F before Q lm

]0s Thermometer in Ihe

Tent = M a

7b

1Dm P before

Q lm

|H(l

in tUo

open Air =

22°

Ciou dy

Motet Weather
Cloudy

Moist Weather

Alpha Lyrae
Gamma Andromedae
Beta Persei
Delta Persei
Capella
Beta Aurigae
Castor

At

At

At

At

At

20h 52m P before Q an Us ThemUOTnetcr in the Tent <K°
l4h 26m, P before Q iiri 2;! Thermometer tn the Tent 3B 0,

En the Air 28 °

2Oh 00m P before Q 0m 59s Thermometer in the Tent 44°.

Thermometer in the Air 45°.

And the Vibration of the Pendulum 1° 35 1 on each side of 0.

14h 37m P before Q 48. 5s Thermometer in the Tent = 40°. Rain great part

Out = 44°. of the Night

17h 35m P before Q 47. 0s

20h 00m P before Q 45. 5s Thermometer in the Tent 43°.

out in the Air 45°,

And the Vibration of the Pendulum = 1° 40'

1

1

0

7

5

4

7

20 +

15+

5+

5+

50-

55+

35-

6

5
4

6
4
6
6
6
9
6
6
9
6
8

4h 28m 40s
30m 18s+
32m 5. 5s

44-
00 -
41-
1. 5
16. 5
3-

16. 5
27
19-
47
2
1

31 +
16. 5

36.0
4. 8

30.2
10.5

7.7

35.0

29.2

1

1

0

7

5

4

7

21

16

6

5

47

57

33

36.0

4.8

30.2
10.5

52.3
35.0
30.8

243

5h 25m 3s
26m 40s
At

9h 55m 21s
55m 20s-

At

j- Equal Altitudes of Capella

7h 30m P before Q 38s; Ther. 27° Hence passed the Meridian
14h 00m Ther. in the Tent 22°. by the Clock at 4h 57m 40s+

in the Air* 20°.

15h 21m P before Q 35s^

25 Christmas

Cloudy

At 18h 35m P before Q 33s Ther. 43°.

At

2Oh 00m P before Q 33 s

Ther. in the Tent 44°,

out

46°.

At

3h 00m P before Q 29.

5s. Ther. in 36°.

1

1 Moist weather

out 36°.

1

> with a little rain:

At

14h 00m

Ther. in the Tent

38°. (

l The Snow that fell

out

37°. j

' 2nd & 3rd nearly gone

151

1766

December

26

27

Cloudy

Moist Weather

18h

30m

P

before Q 22s

2 Oh

00m

P

before Q 21s+

Ther.

in the Tent

45°.

out

47°.

21h

00m

Ther.

in the Tent

45°.

in Air

48°.

15h

00m

Ther.

in the Tent

38°.

in Air

41°.

At 18h

40m

P

before Q

9s

Ther.

in Tent

40°.

out

44°.

2 Oh

00m

P

before Q

8. 5s

Ther.

in

40°.

out

42°.

Vibrations
1° 40 ■

P before <3 Us,

Star Name

29

30

Nearest Point
on the Sector

Revolutions
and Seconds on
the Micrometer

Difference

Apparent
Zenith Distance

0

t

R

it

i

it

o

t

n

Alpha Lyrae

1

20+

5

13+

1

35. 3

1

21

35.3

3

22

Fair and

Gamma Andromedae

1

15+

8

19

1

4. 0

1

16

dry all

9

31

day

Beta Persei

1

5+

9

17. 5

1

29. 5

0

6

11

3

Delta Persei

7

5+

12

16+

0

9. 7

7

5

9.7

12

26

Capella

5

50-

6

32

2

9. 0

5

47

After these, by Accident Occasioned by a strong gust of wind the Plane was moved
out of the Meridian.

Thermometer in the Tent 20°.

out 17°.

Thermometer in the Tent 21°.

out 18°.

Thermometer in the Tent 31°. Vibration
out 26°. 1° 35'.

At 7h 44m P before Q

3s

15h 00m Q before P

0s

28 Sun.

At 2Oh 00m Q before P

2s+

Fair and

Wound up both Clocks

dry

At 21h 00m P before Q

lm 15,

Alpha Lyrae
Gamma Andromedae
Beta Persei
Beta Aurigae

20+

1

1

0

4

4h

At 5

Snow Packed up the Sector.

At 21h 00m P before Q lm 5. 5s

244

15+

4

14

1

5

26-

5+

2

42.5

1

4

27

55+

8

14-

2

11

13+

28m 41s

5h 20m

59 s 9h

53m

9s

30 22+

22

47-

53

9

32 10

24

30.5

53

11.5

57 00 P before Q lm 12s

16:: In the Evening Brought the Plane in to the
29 Meridian and made the following Observations,

3.7

3. 7
28. 5
35.6

16

6

57

Equal Altitudes of
Capella. Hence passed
the Clock at
4h 56m 35s

Ther. in the Tent 20°.
out in Air 15°.

Fair and
dry: The
Snow a
foot deep.

Ther. in Tent 28 .

in Air 28°.

Ther. in Tent 29°.

in Air 28°.

Ther. in Tent 3 2°.
in Air 32°.

44 46. 5 /> Equal Altitudes of Capella. Hence passed

46 4. 5 j by the Clock at 4h 55m 59s.

Ther. in Tent 17°.
in Air 14°.

14h 30m Thermometer in the Tent ^ above 0. P before Q 47. 5s.

* in the Air 3° below 0.

At 16h 53m P before Q 48s 245

4h 55m P before Q lm 1. 5s

At 21h 00m P before Q 53. 5s

4h 5m 52. 5s 5h 43m 24s+'j

7 12

8 34

At 6h 00m P before Q 49s

152

1766

December

31

fair

weather

1767

January

fair and

clear

weather

2

3

4 Sunday
Very wet

5

Rain
Snow
all gone

6

Very

much

rain

7

3h 50m 26s

Clear 51m 39s+

weather 52m 56. 5s

8

fair

weather:

fair

and

clear

4h 4m 48s
6m 7. 5s
7m 30s-

At 21h 00m P before Q 48s Thermometer in the Air 18°.

in the Tent 20°.

At 3h 00m Thermometer in the Air 7° below zero.

in the Tent 0°.

Found Q stopped, or at Rest: Q pointed at 2h 51m: I set Q going again.

At 5h 00m P before Q 17m 5s Thermometer in the Tent 3° below zero.

in the Air 13° below zero.

At 13h 50m (before sunrise) Thermometer in the Tent 10° below zero. froid

in the Air 20 u below zero.

found Q at rest again

At 19h 30m

4h 10m 33s
11 55

13 19.5

At 5h 50m

40

At 13. 5 (before sunrise)

Thermometer in the Tent 21° above zero.

in the Air 17° above zero.

Vibration 1° 12 1

5h 37m 45s

39 10 Equal altitudes, Capella. Hence passed

31- at 4h 55m 32s.

Thermometer in the Tent 3° below zero.

in the Air 12° below zero.

Vibration 1° 10'
Thermometer in the Tent 9° below zero.

in the Air 22° below zero.

At 17h Vibration 1° 5' The Pendulum swings a little farther from zero
on the West Side, than the East: The Clock faces the North. In
rectifying the Instrument for the Equal Altitude; the immediate touch
of the Brass was like patting one's Fingers against the points of
Pins and Needles; the cold was so intense.

At 21h 25m Thermometer in the Tent 21 . Vibration 1 V
in the Air 15°.

3h 45m Thermometer in the Tent 9°.

out 5°.

14h (before sunrise) Thermometer in the Tent 11°.

in the Air 9°.

Thermometer before sunrise in the Air 34°.

At 22h 30m Thermometer in the Tent 39°. Vibration 1 20'. Rain

in the Air 39°.

At 16h Thermometer in the Tent 37°.

Thermometer in the Air 37°.

At 21h Set Q agoing J .

21h 57m P before Q 8m 47s+Vibrations P 1° 35 . The Pendulum

rather swings now farthest on the East Side. Thermometer in the Tent 48 q .

14h 00m Thermometer in the Air 49°.

At 21h 00m Thermometer in the Tent 53°. Rain all the Morning.

in the Air 54°.

At 5h 30m Thermometer in the Tent 43°.

out in the Air 44°.

At 22h 8m P before Q 8m 26s Thermometer in the Tent 46°.

Sum

5h 55m 8. 5s 9h 48m 05s )

56m 27s 9h 48m 6s+ \ Equal Altitudes of Capella.

57m 41. 5s 48m 7. 5s) Hence the star passed at 4h 54m 3s.

At 6h Thermometer in Tent 25°.

Air 26°.

14. 5 (before sun rise Thermometer in the Air 28°.)

Sum

5h 40m 3s 9h 47m 33s \ Equal Altitudes of Capella: Hence

41m 24s 47m 35s > star passed at 4h 53m 46s.

42m 44. 5s 32 *

At 5h 43m Thermometer in Tent 23 .

At 12h 59m 30s The first Satellite of Jupiter Immerged.

At 12h 59m 30s Thermometer in the Tent 20°.

At 14h 30m Thermometer in the Air 17°.

Vibration 1° 40'

246

153

1767

January

9

10

fair

and

moderate

weather

11 Sunday

13

fair weather

14

Cloudy with

At 22h 00m P before Q 8 m 7s Thermometer in Tent 40° Vibration

Air 400 lO 351 +

The Pendulum swings 8 ’ more East than West
At 23h 11 m Thermometer in the Tent 430

6 h 21m 28s 8 h 2 m 45s )

22 m 43s 4m 3s > Equal Altitudes of Castor

24m 00s 5m 18s-)

At 7h 34m 18s The first Satellite of Jupiter Immerged
7h 38m Thermometer in the Tent 25°

At 22h 14m P before Q 7m 50s Thermometer in the Tent 50°

14h 30m Thermometer in the Air--cloudy in the Air 47°

At 23h 25m P before Q 7m 43s Thermometer in the Tent 42°

in the Air 44°

I now wound up Q

At 21h 50m P before Q 8 m 2s Thermometer in the Tent 42°

in the Air 45°

Vibration 1° 40* The Pendulum swings to the Eastward as
on the 9th day

At 16h 00m Thermometer in the Air 23° in the Tent 23°

At 21h 45m P before Q 7m 53s thermometer in the Tent 33°

in the Air 33°

snow and rain

16h 30m

Thermometer in the Air 33°

15

At 21h 35m

P before Q 7m 44s Thermometer in the Tent 39°

cloudy

in the Air 41°

At 16h 00m

Thermometer in the Tent 30°

in the Air 30°

16

At 21h 34m

P before Q 7m 33. 5s thermometer in the Tent 39°

in the Air 370

fair

Vibration

1° 35' and the Pendulum swings to the East as before

4h

5m

4s+

5h 35m 23s

9h 43m 13s) Equal Altitudes of Capeila. Hence star

6

25

36 47

9 43 12 > passed at 4h 51m 36s

7

50

38 7

43 11+)

At 5h 40m

Thermometer in the Tent 24°

in the Air 21°

17h 00m

Thermometer in the Tent 28©

in the Air 25°

17

At 22h 4m

P before Q 7m 26s Thermometer in the Tent 43°

Cloudy

in the Air 39°

most of

At 16h 30m

Thermometer in the Tent 33°

the night

in the Air 31°

18 Sunday

At 23h 37m

P before Q 7m 18s Thermometer in the Tent 39°

in the Air 39°

At 16h 20 m

Thermometer in the Tent 25°

in the Air 260

At 22 h 25m

P before Q 7m 11s Thermometer in the Tent 39°

in the Air 36 o

fair

Now wound up Q

weather

4h

4m

8.5s

5h 34m 44s

9h 41m 36s ) Equal Altitudes of Capeila. Hence

5

27.5

36 8

9 41 35. 5 > star passed at 4h 50m 48s

6

52

37 29

41 37.5)

At 5h 40m

Thermometer in the Tent 21°

in the Air 18°

20

Cloudy

At 23h 40m

Thermometer in the Tent 390 p before Q 7m 36s

in the Air 40°

At 16h 00m

Thermometer in the Tent 39°

in the Air 390

21

Fine

At 22h 33m

P before Q 7m 27. 5s Thermometer in the Tent 40°

temperate

in the Air 40°

weather in

At 15h 20m

Thermometer in the Tent 23°

the Afternoon

in the Air 21° Began to snow

22

At 23h 00 m

P before Q 7m 21. 5s Thermometer in the Tent 27°

in the Air 27°

Vibration 1 ° 30* and the Pendulum swings 8 ‘ or 10' more East than
West as before

At 15h 30m Thermometer in the Tent 25° „ 0+ni

in the Air 23° Sn ° Wmg stl11

247

248

Snow

154

1767

January

23

24

Cloudy

Rain freezing„

25 Sun

27

At 23h 20m P before Q 7m 17s Thermometer in the Tent 32o

in the Air 32°

At 16h 00m Thermometer in the Tent 32°

in the Air 32°

At 23h 00m P before Q 7m 9s Thermometer in the Tent 43°

in the Air 40°

Vibration 1° 30' and the Pendulum swings as before.

Wound up P.

At 15h 30m Thermometer in the Tent 32°

in the Air 32°

At 23h 15m P before Q 6m 59s+ Thermometer in the Tent 31°

in the Air 30°

At 15h 30m Thermometer in the Tent 28° „ . _

in the Air 27° Rain freezing.

At lh 00m P before Q 6m 49. 5s Thermometer in the Tent 32°

in the Air 32°

Wound up Q

At lh 25m P before Q 7m 30s

15h 23m Thermometer In the Tent 21°

in the Air 20°

At Oh 40m P before Q 7m 19. 5s Thermometer in the Tent 27°

in the Air 250

Snow

Cloudy with
rain—
freezing

249

Rain and
freezing

3h 32m 53s
34m 5s-
35m 19. 5s

6h

2m 7 s
3m 21.5s
4m 34.5s
At 6h 7m

9h 37m 26. 5s
9h 27m 26s-
37m 27, 5s
Thermometer

Equal Altitudes of Capella.
star passed at 4h 48m 43s

Hence

At 15h 40m Thermometer

28

in the Tent 15°
in the Air 12°
in the Air 11°
in the Tent 140

Clear weather but these three days past, rain and froze the moment it fell on the
trees or ground; such that the limbs of the Trees broke in a surprising manner,
with the weight of clear Ice upon them.

At 23h 15m P before Q 7m 11s Thermometer in the Tent 36<>

Vibration 1° 20' and Pendulum swings as before.

At 15h 43m Thermometer in the Tent 15°

in the Air 13°

P before Q 7m 2s Thermometer

30

31

February
1 Sunday

At Oh 5m

At 16h 26m

At 23h 40m

Vibration
At 17h 15m

At lh 5m

At 15h 40m

At 23h 20m
At 15h 40m
At 23h 30m

Thermometer in the Tent 16°
in the Air 16°

P before Q 6m 54s Thermometer

1° 20' and Pendulum swings as before.
Thermometer in the Tent 32°

in the Air

32°

in the

Tent

35°

in the

Air

340

in the

Tent

310

in the

Air

35°

in the Air 35 c

Rain

P before Q 6m 44s
Thermometer

Thermometer

in the Tent 36°
in the Air 36°

Snow

Rain

in the Tent 36°
in the Air 35°

P before Q 6m 34. 5s Thermometer
Thermometer in the Tent 15°

in the Tent 36°
in the Air 37°

Clear weather

in the Air 13°

P before Q 6m 28s Thermometer in the Tent

in the Air

Wound up Q

At 15h 40m Thermometer in the Tent

in the Air

40

34°

Clouds

clear

16<>

15°

155

1767

February

3

4

3h 34m 52s-

36 5

37 20

5

6

7

8 Sunday

3h 55m 32s
56 50+

* ft w

9

10

11

12

13

14

15 Sunday

16

At 23h 55m P before Q 7m 3s Thermometer in the Tent 41°

, in the Air 38°

Vibration 1° 30’ and the Pendulum swings to the East as before
m 12. 5s 6h 36m 10. 5s 1

22 37 24 > Equal Altitudes of Beta Aurigae.

35+ 38 34 ) Windy

4h 21m 12. 5s
22 22
23 35+

At 6h 40m

22 37 24 > Equal Altitudes of Beta Aurigae.

35+ 38 34 ) Windy

6h 40m Thermometer in the Tent 26°
in the Air 25°

15h 44m Thermometer in the Tent 14°
in the Air 10°

23h 10m P before Q 6m 56s Thermometer in the Tent 34°

in the Air 32°

Vibration 1° 30 1 and Pendulum swings as before
tn 0. 5s Sum: 9h 33m 20. Ss'j

16+ 33 21+ iEqual Altitudes of Capella: hence this

29 33 21- ) star passed at 4h 46m 40. 5s by the clock

6h 0m Thermometer in the Tent 24°
in the Air 23°

16h 0m Thermometer in the Tent 30°
in the Air 32°

Oh 20m P before Q 6m 48s Thermometer in the Tent 45°

in the Air 41°

15h 57m Thermometer in the Tent 13°
in the Air 12°

19h 00m Vibration 1° 30* Pendulum swings as before
Oh 15m P before Q 6m 4s+ Thermometer in 28° Cloudv

out 240 y

16h 54m Thermometer in the Tent 13°, in the Air 12°

Oh 0m P before Q 6m 39s Thermometer in 34°

out 36° Cloudy

16h 54m Thermometer in the Tent 250; in the Air 24°

22h 10m Thermometer in the Tent 54° Hazy
in the Air 52° *

23h 15m P before Q 6m 33s
i 5. 5s 17. 5s^

26 16.6 > Equal Altitudes of Capella, hence this star

45.5 17.5 ) passed at 4h 45m 38.5s

At 15h 44m

At 23h 10m

5h 56m 0. 5s

57 16+

58 29

At 6h 0m

15h 57m

19h 00m
At Oh 15m

16h 54m
At Oh 0m

16h 54m
At 22h 10m

Cloudy

Cloudy

23h 15m
5h 33m 5. 5s

34 26

35 45.5
At 5h 40m

Thermometer in the Tent 33°, in the Air 32°

Vibration 1° 35 1 and Pendulum swings East as before

At 16h 30m
At Oh 0m

16h 30m

At 18h 40m
At 23h 56m

Thermometer in the Tent 32°, in the Air 32°

P before Q 6m 25.5s Thermometer in 42° f

out 41° Cloudy

Thermometer in Tent 41°, in the Air 41°. Thunder
and Lightning in the Night

Wound up Q which had been let go down and stop for some Hours.

At 23h 56m P before Q 2m 45s Thermometer in 34° Clo

out 35° we<

16h 37m Thermometer in the Tent 25°, in the Air 25©

At 23h 35m P before Q 2m 37s Thermometer in the Tent 40°

in the Air 38°

Pendulum swings East as before
This afternoon took down Q.

Cloudy and hazy
weather

Vibration
1° 40'

At 16h 25m
At 23h 25m
At 16h 23m
At Oh 20m
17h 22m
At 17h 00m
At lh 45m
16h 42m
At 23h 55m

Thermometer in the Tent 30°, in the Air 29°
Thermometer in the Tent 38°, in the Air 41°
Thermometer in 31°, out 31°

Thermometer in the Tent 32°, out 33° Cloudy
Thermometer in the Tent 28°, out 24°
Thermometer in the Tent 26°, in the Air 27°
Thermometer in 34°, out 33°

Thermometer in 18°, out 10°

Thermometer in Tent 39° in the Air 48°, Haz

Cloudy

At 13h 44m 50s The first S atellite of Jupiter not immerged.

Flying

13h 46m 25s The first Satellite of Jupiter was immerged. Clouds
16h 48m Thermometer in the Tent 28°, out 17°

156

Going of P

December 24 4h

28 4

30 4

January 4

7 4

8 4

16 4

19 4

27 4

February 4 4

8 4

25 4

Per day
loses

57m

40s

16.3s

56

35

18.0

55

59

13.4

55

32+

54

17.0

53

46

16.30

36

50

48

48

43+

46

40.5

45

38.5

15.9

41

8**

Note:

When the Clock was stopped and the Point of Pendulum at rest
it hung over at 8 T or 10 T to the East of zero* lt T s my opinion
the arch was not altered, but that the Post of the Clock settled after
the extreme cold so much Eastwards.

253

Apparent Times of the Eclipses at Paris

December 16
January 8
10

22h 58m 13s
22 55 50

17 23 21

Right Ascension of Sun 16d = 17h 36m 39s
5 17d = 17 41 05

4 26

As 24h : 4m 26s :: lh :
Then I7h 41m 5s - Us

Llm

: 17h 40m 54 s

Right Ascension of Sun at the Eclipse

5h 42m 51s = Beta Aurigae passed
5 42 26 = Right Ascension of Star

0m 25s = Clock slow when star passed
+ 4

"0m 29s = Clock slow at the Eclipse

Then 24h : 16s 5h 43 m : 4s

Hh 26m 00s the Eclipse according to the clock
+ 0 29

llh 26m 29s = Right Ascension Mid Heaven at the Eclipse
17h 40m 54s = Right Ascension Sun then

December 16,
December 16,

17h 45m 35s Apparent Time
22h 58m 13s

5h 12m 38s Difference according to the Eclipse,

16d

4h 41m 37s
4h 37m 15s

Complement = 19h 18m 23s = Sun's Right Ascension 8d
Complement > 19h 22m 45s = Sun's Right Ascension 9d
4m 22s

157

24h : 4m 22s :: lh 4m : 11s

Then 19h 22m 45s - 11s = 19h 22m 34s = Sun's Right Ascension
4h 53m 46 s+ Capella passed by the clock
4h 59m 33s = Right Ascension of Capella
5m 47s = Clock slow
+ 3s

5m 50s = Clock slow at the eclipse
As 24h: 16s :: 8h : 5s

12h

59m

30s

t 5

59

13h

5m

29s

19

22

34

17h

42m

46 s

22

55

50

5h

13m

04s

Eclipse by the clock

= Right Ascension Meridian at the Eclipse
= Right Ascension of Sun

- Apparent time at Brandywine

- Difference in Meridian by that 8d.

4h 32m 54s Complement = 19h 27m 6s = Sun's Right Ascension lOd.
4h 28m 34s Complement = 19h 31m 26s = Sun's Right Ascension lid.

4m 30s

As 24h : 4m 20s 6h 37m : lm

4h 53m 46s

0m 32s fast

4h 53m 14s = Capella passed by the clock

4h 53m
7 34

2h 41m

As 24h : 16s 2h 41m : 2s

1767

February

17

20

21

22 Sun.

23

24

7h 34m 18s
+ 6 19

7h 40m 37s
19h 30m 15s
12h 10m 22s
17h 23m 21s
5h 12m 59s

Right Ascension Mid Heaven at the Eclipse
Right Ascension of Sun
Apparent Time at Brandywine

Difference Meridian by that on the lOd.

At Oh 15m

At lh 30m

21h 25m
At 23h 45m
At 17h 30m
fair and clear
Snow
Ditto

Thermometer

Thermometer

Thermometer

Thermometer

Thermometer

in the Tent 28°
in the Air Ditto
in the Tent 39°
in the Air 44°
in the Tent 46°,
in the Tent 48°,
in the Tent 14°,

in the Air 55°
in the Air 59°
in the Air 12°

Sum

4h 11m 43s-
13 21

15 7

5h 7m 9s
8 55. 5

10 32+

9h 22m 16s- j

22 16. 5 > Equal Altitudes of Capella

22 15 ) Hence the star passed the Meridian at

4h 41m 8s- by the Clock

At lOh 42m 50s the 1st Satellite of Jupiter Immerged, very

dubious by its near approach to Jupiters Limb.

N. B. The Eclipses of the Satellites of Jupiter were observed

with a Reflecting Telescope that magnified it about 70Times,

26 Fair and pleasant weather

27 Fair and pleasant weather

158

1767

February

2R

March

1 Sun.

2

3

4

5

6

9

10

11

12

13

14

15 Sun.

16

17

18

Took down and Packed up the Clock belonging to the
Royal Society. The Pendulum swings

to the Eastward as before. Vibration 1° 40*. The Index
stands at 3, or rather about a line minus of 3. The
point of the Pendulum swings something farther back from the arch
(showing the degrees and minutes) than it did when it was set up.
The Clock was fixed to a piece of Sawed* Timber 22 Inches
in breadth and 5 1/4 inches thick. The said piece of Timber was;
four feet into the ground, which was composed of a very firm,
dry, hard clay.

* Sawed on all sides forming an oblong square,

At 2h P. M. The Thermometer in the Air 69°

At 2h P. M. Thermometer
At Ditto
At Ditto
At Ditto

At 3h 30m P. M.

At lh P. M.

At 2h Ditto
At 3h Ditto
At 2h P. M. Ditto
At 3h Ditto

in the Air 56°

460

57°

49°

51°

51° Rain
48° Rain
56°

51°

50°

At about Sunrise
2h P. M.

At about Sunrise
2 P. M.

At 3h Ditto
At 2h P. M.

At 2h 30m Ditto

At 2h Ditto

In the Morning Snow

11 °

26°

7°

28°

36°

47°

71 °

67°

Left Brandywine and proceeded to New Town on
Chester River in Maryland to attend the Gentlemen
Commissioners the 24th Instant according to t eir
appointment made at Christiana Bridge in November last

At Ditto . .

At Ditto: The Commissioners not arriving we

set out for Annapolis

Note:

rhe Thermometer in the Air was placed on the North
side of a House (suspended from the end of a stick) about

two feet from me wan.

That in the Tent, by the outside of a Clock Case with a
Blanket around it, which surrounded the Clock.

255

256

159

Aberration of stars observed at the Middle Point in October 1766.

h

m

s

h

m

s

Alpha Lyrae mean 17" 6

Beta Persei k

11

18

20

k

2

24

55

Sun lid lh

6

18

12

mean 9"6

0.9823

bun Uct. lid llh

6

10

37

6

Sine

9.0561

9

13

35

17.6°

1.2455

03

O

H

1

0. 0384

2

16

25

Sine

9.9877

Beta Persei

11

18

20

Alpha Lyrae

—17”11

1.2332

Sun 15d 7h

6

52

24

mean 9"6

0.9823

k

2

24

55

6

10

44

Sine

9. 2701

Sun 15d 22h

6

23

3

-11*79

0. 2525

9

17

58

1. 2455

2

12

2

Sine

9.9783

Delta Persei k

11

0

55

-16"74

1.2238

Sun lOd 20h

6

18

00

id' 4

1. 0170

h

m

s

5

18

55

Sine

9.2838

Delta Cygni

k

2

11

35

+2l'00

0.3008

Sun 12d Oh

6

19

9

181*4

Delta Persei

11

0

55

9

0

44

1. 2648

Sun 15d 7. 5h

6

22

27

2

29

16

Sine

9.9999

5

23

22

1. 0170

Delta Cygni

k

2

11

35

0

6

38

Sine

9. 0626

Sun 16d 23h

6

24

5

1. 2648

+ 11*20

0.0796

9

5

40

Sine

9.9979

h

m

s

2

54

20

-1SJ31

1.2527

Capella k

9

28

50

h

m

a

Sun lid Oh

6

18

17

Gamma Cygni

k

2

6

11

4

16

67

mean Bl'O

0.9031

Sun lid 12h

6

18

40

mean 17 "4

1, 2405

1

13

10

Sine

9. 8355

8

24

51

Sine

9.9982

+ 5.48

0. 7386

- 17:33

1. 2387

Cape 11a

9

28

30

Gamma Cygni

2

6

11

Sun 15d 21h

6

23

0

8"0

0.9031

Sun 17d OOh

6

24

7

1.2405

4

21

30

Sine

9. 7941

9

0

18

Sine

9.9999

+4:'98

0.6972

-17140

1.2404

h

m

s

IT

m

s

Beta Aurigae k

9

8

40

Alpha Cygni

k

2

1

10

mean IB’.'O ■

1.2553

Sun lid 4h

6

18

20

mean 713 5

0. 8663

Sun 12d Ih

6

19

12

Sine

9.9938

3

27

00

Sine

9.9499

8

20

22

-17: f 75

1. 2491

2

3

00

+6l'55

0.8162

Alpha Cygni

2

1

10

Beta Aurigae

9

8

40

Sun 16d 12h

6

23

38

1.2553

Sun 16d 9h

6

23

31

71*35

0. 8663

8

24

48

Sine

9.9982

4

2

11

Sine

9. 9275

-17 , . , 93

1. 2535

1

27

49

+61'22

0. 7938

TT

m

s

* r

Gamma Andromedae k

5

0

1

Castor

0

2

5

Sun lid 5. 5h

* 4l'4

0.6434

Sun Ud Oh

6

18

10

mean ll!'8

1.0719

Sine

9.9031

6

20

15

Sine

9.5392

-31*52

0.5465

-41'08

0.6111

Castor

7

4

45

Gamma Andromedae k

0

2

5

ill’s

1.0719

Sun 16d llh

6

23

35

4l'4

0.6434

Sun 14d 17. 5h

6

21

51

Sine

9.6083

1

28

20

Sine

9.9300

6

23

56

-4 ”79

0.6801

-31*75

0.5734

Sun's Longitude Sun's Longitude

d

h

h

m

s

d

h

h

m

s

Paris

11

11

Alpha Lyrae

6

18

37

Paris

15

29

Alpha Lyrae

6

23

3

1766

12

00

Delta Persei

6

19

9

1766

16

23

Delta Cygni

6

24

5

October

11

12

Gamma Persei

6

18

40

•+->

October

17

00

Gamma Cygni

6

24

7

12

1

Alpha Cygni

6

19

12

to

tti

16

12

Alpha Cygni

6

23

38

11

0

Gamma Andromedae

6

18

10

W

14

17.5

Gamma Andromedae

6

21

51

11

1

Beta Persei

6

18

12

<1)

C

15

7

Beta Persei

6

22

24

10

20

Delta Persei

6

18

00

cti

rH

15

7.5

Delta Persei

6

22

27

11

3

Capella

6

18

17

Ph

15

21

Capella

6

23

00

11

4

Beta Aurigae

6

18

20

16

9.5

Beta Aurigae

6

23

31

11

5.5

Castor

6

18

23

16

11

Castor

6

23

35

Time at Paris of the Observations.
Solar Longitudes from the Conaissance
(des Temps.)

160

Plane West
(Indistinct)

The Aberration of Stars Observed at Brandywine
h m s

in December 1766

Alpha Lyrae k

2

24

55

17 6

Sun 19d 6h

8

27

55

11

22

50

1. 2455

0

7

10

Sine

9.0961

+2"20

0.3416

k

2

24

55

Sun 25d 17. 5h

9

4

35

1.2455

11

29

30

Sine

7.9408

+0i'15

9. 1869“

Gamma Andromedae

k 0.

25

h

m

s

Sun 19d 5. 5h

8

22

50

141'8

1.0319

8

24

55

Sine

9.9983

11V76

1.0702

0

2

5

Sun 26d 21h

9

5

43

1.0719

9

7

48

Sine

9.9960

-111*63

1.0679

h

m

s

Beta Persei

11

18

20

9l*6

0.9823

Sun I6d 8. 5h

8

54

59

Sine

9.9B13

0.9836

Sun 25d 14h

11 18 20
9 4 24

8 22 44

Sine
-9” 56

Delta Persei

k

11

0

55

10?4

Sun lGd 9h

8

20

00

Sine

H 7

25

55

-8l'6I

Sun 24d lh

11

0

55

9

3

23

8

4

18

Sine

9 V 3 7

Plane East

Capella k
Sun 16d 10. 5h

Sun 24d 16h

Beta Aurigae
Sun I7d 9h

Sun 25d 2h

0.9823

9.9982

(L9805

1. 0170
9.9181
9,9351

1, 0170
9,9548
0, 9718

Castor k
Sun 17 d llh

Sun 23d 6h

Paris

19

6

Alpha Lyrae

1766

14

5.5

Gamma Andromedae

December

16

8.5

Beta Persei

16

9

Delta Persei

16

10.5

Capella

17

9

Beta Aurigae

17

11

Castor

Sun's Longitude
8 27 55

8 22
8 24
8 25
8 25

26

26

50

59

0

4

2

7

Paris

1766

December

d

25

26
25
24

24

25
23

h

m

s

9

28

30 mean

8"

0.9031

8

25

4

Sine

9.6019

6

23

34

-3'.'20

0.5050

9

28

30

9

3

28

0.9031

7

1

58

Sine

9.7238

-41*24

0.6269

h

m

6

9

S

40

7?3S

0.8663

8

26

2

Sine

8.9135

6

4

42

o’/go

9.7798

9

8

40

9

3

54

0. 8663

6

12

34

Sine

9.3376

-11*60

0.2039

h

m

s

7

4

45

41*4

0,6434

8

26

7

Sine

9,9337

4

0

52

-31*78

0.5771

7

4

45

9

2

2

4

6

47

0.6434

1

23

13

Sine

9.9036

31*52

0.5470

h

Plane West

Sun's Longitude

17. 5

Alpha Lyrae

9

4 35

21

Gamma Andromedae

9

5 43

14

Beta Persei

9

4 24

14

Delta Persei

9

3 23

16

Capella

9

3 28

2

Beta Aurigae

9

3 54

6

Castor

9

2 2

258

161

(Undated)

Annual Precession

Right Ascensions Stars 1766 in Declination 1766 Nutations

Gamma Andromedae 27°

26'

171* 80

-

71*52

Nutations at the Middle Point

Beta Persei

43° 16'

14l'60

81*21

by the Table I computed before.

Delta Persei

51° 36'

121*46

-

81*35

The following are the Nutations

Capella

74° 52'

51'24

-

71*75

computed at large from the Maximum of 19

Beta Aurigae

850 35'

11*54

71*10

for the deviation of the Obliquity

of the

Castor

109

55'

61*83

+41*60

Ecliptic,

the same as the table before was

Alpha Lyrae

277°

15*

21*53

+6l'05

computed from 171'8

- Equa. of the

Delta Cygni

294°

25'

81*29

+31*95

Precession of the Equinoxes.

Gamma Cygni

303°

30'

111*07

+21*83

Alpha Cygni

308°

22'

12l'45

+21*18

h m

s

Ascending node of moon's orbit from the sun =10-15

- 39

from Vernal Equinox

1 - 14

- 21

(log)

(log)

As Rad

10.

And as Rad

10.0000

S Da V 44° 21' *

9.84450

: Cos DdaV 44° 21'*

9.8543

:: Mean Precession 171*8

1.25042

:: Mn 9l'5

0.9777

: Precession 12l'44

1.09492

: Nutation 6.

79

0.8320

Alpha

Delta

Gamma

Alpha

Gamma

Beta

Delta

Lyrae

Cygni

Cygni

Cygni

Andromedae

Persei

Persei

Cos Star's Right Ascension

9.1010

9.6163

9.7419

9.7929

9.9482

9.8622

9.7932

Precession 12'.'44

1.0949

1.0949

1. 0949

1.0949

1.0949

1.0949

1.0949

Sum

10.1959

10.7112

10. 8368

10.8879

11. 0431

10.9571

10.8881

Cosine Obliquity 23° 2 8'

10.3999

10.3999

10.3999

10. 3999

10.3999

10.3999

10.3999

Equinoctial precession

9.7960

0.3113

0.4369

0.4879

0. 6432

0. 5572

0.4882

-0l'62

+ 2 l r 05

-2:'7 4

-31*08

-41*40

-31*61

-31*08

Capella

Beta

Castor

Aurigae

Cos Star's Right Ascension

9.4167

8.8865

9. 5323

Precession

.1.4942

_-1. 0949 _

.1., 0949

Sum

10.5116

9.9814

10.6272

Cosine Obliquity

10.3999

10.3999

10.3999

(Sum)

0. 1117

9.5815

0. 2273

Beta

Equinoctial precession

-11*29

-0"38

-11*69

Capella

Aurigae

As Rad

10.0000

1. 0000

1.0000

1.0000

1.0000

1.0000

1.0000

1. 0000

1.0000

: Sine Right Ascension

9.9965

9.9593

9.9211

9.8943

9.6634

9.8359

9.8941

9.9847

9.9987

:: Nutation 6i r 79

0.8320

0.8320

0. 8320

0. 8320

0. 8320

0.8320

0.8320

0.8320

0. 8320

:Equa. Obliq.

0.8285

0.7913

0. 7531

0. 7263

0.4954

0.6679

0. 7261

0. 8167

0.8307

+6.74

+6.19

+5.66

+5.33

-3. 13

-4.66

-5.32

-6. 56

-6.77

-0.62

+2.05

-2.74

-3.08

-4.40

-3.61

-3.08

-1.29

-0.38

Combined

+6 !'12

+41 1 14

+21*92

+21*25

-71*53

-8. h 27

-8*.' 40

-7785

-71' 15

Castor
1.0000
9.9732
0.8320
0.8052
+6.39
-1. 69
+4:'70

* Editorial note: This probably denotes the angle from the
vernal equinox to the ascending node of the moon's orbit.

259

(Undated) For the Nutations at Brandywine in December, 1766

Longitude of Ascending Node of Moon = 10s 12° 6'
a' Vernal Equinox = 37° 54'

:: Mean Precession 17"8
: Precession 13! 21
As Rad : cosine 37° 54'

:: Mn 91*5
: Nutation 61*37

(log)

9. 8704
1.2504
1. 2208 and
9. 8263
0.9777
0. 8040

Then Cosine star's R. A,
Precession 13*.'21

Sum

Cosine Obliquity

Equi. Precession

Alpha

Lyrae

9.1080

1. 1208

Gamma

Andromedae

9.9482

1. 1208

Beta

Persei

9.8622

1. 1208

Delta

Persei

9.7932
1. 1208

Cape 11a
9.4167

1. 1208

Beta

Aurigae

8. 8865

1. 1208

Castor
9.5323
1. 1208

10.2218
10.3999

11.0690

10.3999

10.9830

10.3999

10.9140

10.3999

10.5375

10.3999

10.0073

10.3999

10.6531

10.3999

9.8219
+0766

0.6691

-4'.’ 67

0.5831
-37 83

0.5141
-37 29

0.1376

-i:*37

9.6074

-0740

0. 2532
-17 79

As Rad

: Sine Star’s R. A.

Nutation 6.*'07

10.0000
9.9965
0.8040

10.0000
9.6634

0.8040

10.0000
9.8359
0.8040

10.0000
9.8941
0.8040

10.0000
9.9847

0.8040

10.0000
9.9987

0.8040

10.0000
9.9732
0.8040

, ♦ ii UlClllvit v « w i

:: Equi. Nutation

Obliquity

*FVm i Precession

0.8005
-6.32
+0.66

0.4674

-2.93

-4.67

0.6399

-4.36

-3.83

0.6981

-4.99

-3.27

0.7887

-6. 15
-1.37

0.8027

-6.35

-1.40

0. 7772

+5. 99
-1.79

Combined

By the Table Computed before

-5.66
-5'.'66

-7.60

-7 "60

-8.19

-Sl'lS

-8.26

-8"24

-7.52

-7'.'48

-6.75

-6'.' 77

+4. 20

+4:'ie

1766

October

Mean

Aberration
Nutation
Prec. lid 1766
Refraction
Mean Zen. Dist,
11 Oct. 1766

Plane of the Sector EAST

Alpha Lyrae Delta Cygni Gamma Cygni

10

11

12

7 19.0
7 20.7
7 22.0

11 6
12 6

6 51.0
6 51.0

10 1 3 52.3

11 1 3 52.0

12 1 3 51.0

Alpha Cygni
o i "

11 6
12 6

5. 5

3.5

4.5

Gamma Andromedae

o i M

8 2 44 28. 7

10 2 44 30.6

11 2 44 30.7
44 27.2
44

12

lldTEh 0 7 20.57"

51. 0

-18.40

l 51.77

-17.33

-17.75

29. 2

- 4.0

+ 6. 12

+ 4, 14 + 2.62

+ 2,25

- 7.5

0. 00

0,00 o.po

0.00

0,00

+ 0.12

+ 6.11 + LP6

+ 6.00

+ 2. 75

0 7 9.70

6 6 42.85 |l 3 38.42

5 59 55.00

2 44 20.39

Alpha Lyrae
o 1 T '

Plane of the Sector WEST
Delta Cygni Gamma Cygni

o i » o i fi

Mean

Aberration
Nutation
Precession
Refraction
Mean Zen. Dist.
October 11, 1766
Ditto Plane East

13

14

0

7

21.0

15

0

7

22.7

15

6

16

0

7

22.7

17

0

7

23.3

18

18

G

0

7

22.42

6

-16.74
+ 6 . 12
- 0. 03

+ 0 ,. 12 _

0 7 11.89 6

0 7 9.70 6

Mean Zen. Dist.
Oct. 11, 1766
at Middle Point
Ditto at Brandywine

0 7 10. 79 6

1 21 36.42S

Difference between
Brandywine and
Middle Point

1 28 47. 21

6 58.0

6 59.3

6 58,65

-18. 31
+ 4. 14
- 0, 14
+ 6.11
6 50.45

6 42. 85

15 1 3 54.7

16 1 3 55.5

17 1 3 56.0

18 1 3 56.0

1 3 55.55

-17.40
+ 2.92
- 0. 18
+ 1.06
1 3 41.95

1 3 38j42

3 40j 18

Alpha Cygni

Gamma Andromedae

o

i

11

o

i Tl

13

2

44 35.3

14

6

0

0, 0

14

44 36.0

15

6

0

1. 2

15

44 35,5

16

6

0

0, 5

17

5

59

59.5

18

6

0

2,3

6

0

0.70

2

44 35.57

-17.93

- 4,79

+ 2,25

- 7,53

- 0. 19

- 0.19

+ 6,0

+ 2.75

5

59

50. 83

2

44 25.81

5

59

55. 00

2

44 20.39

5

59

52.92

2

44 23.10

1

15 38. 19

1

28 44.91

261

163

1766

October

Plane of the Sector EAST

Beta Persei
o 1 "

Delta Persei

O 1 »»

Cape 11a

0 i "

Beta Aurigae

0 i m

Castor

O 1 »'

8

1

34

54.0

8

8

33 35.0

8

7

16 21.3

8

6

26

3.2

8 6

4 50.5

10

1

34

53.5

10

8

33 34.5

10

7

16 20.0

10

6

26

4.0

10 6

4 50.5

11

1

34

55.7

11

7

16 20.3

11

6

26

4.0

11 6

4 49.5

12

1

34

55.0

12

8

33 33.0

12

7

16 22.0

12

6

26

4.0

12 6

4 52.0

Mean

lid llh

1

34

54.55

8

33 34.7

7

16 20.90

6

26

3. 80

6

4 50.62

Aberration

- 1.09

+ 2.00

+ 5.48

+

6. 55

- 3.52

Nutation

- 8.27

- 8.40

- 7.85

-

7. 15

+ 4.70

Prec. lid 1766

0.00

0.00

0.00

0.00

0.00

Refraction

+ 1.58

+ 8.55

+ 7.26

+

6.43

+ 6.08

Mean Zen. Dist,
11 Oct. 1766

1

34

46.77

~8~

33 36.32

T

16 25.79

TT

26

9.63

6

4 57.88

Sector WEST

Beta Persei

Delta Persei

Capella

Beta Aurigae

Castor

0

i

IT

o

i

II

o

t

" |

o

i

ii

o

i

it

13

1

35

0.7

13

8

33

37.5

13

7

16

27.5 ;

14

35

0.6

14

33

40.4

14

16

29.7 ;

14

6

26

11. 5

14

6

4

48.0

15

35

0.0

15

33

38.0

15

16

27.5 1

15

26

11.8

15

4

47.3

16

35

0.0

16

33

36.5

16

16

29.3

16

26

10.5

16

4

49.5

17

16

27.5

17

26

11.3

17

4

48.4

Mean

1

35

0.33

_

33

38. 10

7

16

28.30

T

26

11.38

6

4

48.30

Aberration

- 1.79

+ 1.20

+ 4.98

+ 6.22

- 3.75

Nutation

- 8.27

- 8.40

- 7.85

- 7. 15

+ 4.70

Precession

- 0.16

- 0. 14

- 0.07

- 0.02

- 0. 10

Refraction

+ 1.58

+ 8.55

+ 7.26

+ 6.43

+ 6.08

Mean Zen. Dist.

1

34

51.69

IT

33

39.31

7'

16

32.62

IT

26

16.76

6

4

55.23

Oct. 11, 1766

Ditto Plane East

1

34

46. 77

8

33

36.32

7

16

25.79

6

26

9.63

6

4

Mean Zen. Dist

Oct. 11, 1766

1

34

49.23

8

33

37.82

7

16

29.20

6

26

13.20

6

4

56.56

at Middle Point

Ditto at Brandywine

0

6

4.83

7

4

53.84

5

47

40.60

4

57

28. 11

■7

33

Difference between

Brandywine and

1

28

44.40

1

28

43.98

1

28

48.60

1

28

45.09

1

28

44.34

Middle Point

262

1766

December Plane of the Sector EAST

Alpha Lyrae Gamma Andromedae Beta Persei

o

r

H

o

t

ti

13

1

(15

54.8

13

0

6

20.3

15

1

is

55.0

15

0

6

21.7

16

b

55.7

16

0

6

21.0

19

0

6

20. 2

o

i

ii

17

1

21

42.0

19

1

21

43.5

21

1

21

41.7

Mean

1 21 42.40

1 15

55. 17

0

6

20.80

Aberration

+ 2.20

-11. 76

- 9.20

Deviation

- 5.66

- 7.60

- 8. 19

Precession

+ 0.48

- 3. 12

- 2.64

Refraction

+ 1.36

+ 1.26

+ 0. 10

Mean Zen. Dist, 11th Oct. 1766

1 21 40.78

1 15

33. 95

0

6

00. 87

Plane East

164

1766

December Plane of the Sector WEST

Alpha JLyrae Gamma Andromedae Beta Persei

o

i

II

o

i

ti

o

1

it

21

21

0

6

29. 7

24

1

21

36. 0

24

1

16

4.8

24

0

6

30. 2

27

21

35.3

27

16

4.0

27

6

29. 5

28

28

16

3.7

28

6

28. 5

Mean

1

21

35.65

1

16

4, 17

0

6

29.48

Aberration

+ 0 k 15

i

-11.63

- 9.56

Nutation

- 5.66

!

j

!

- 7.60

- 8. 19

Precession

+ 0.53

|

- 3.76

- 3.05

Refraction

+ 1.36

+ 1.26

+ 0. 10

Mean Zen. Dist., 11 Oct. 1766

1

21

32. 03

1

15

42.44

0

6

8.78

Ditto Plane East

1

21

40.78

[ 1

15

33.95

0

6

0. 87

True Mean Zen. Dist. Oct. 11, 1766

1

21

36.42

; l

15

38. 19

0

6

4. 83

True Zen. Dist. Observed at Brandywine

in Jan. & Feb. 1764 reduced to

1

21

44. 2

l

14

50.8

0

5

25.5

1st Jan. 1764

Precession to Oct. 11, 1766

- 7.03

+49.45

+40.56

Reduced to Oct. 11, 1766

1

21

37. 17

l

15

40.25

0

6

6.06

Alpha Lyrae Delta Cygni Gamma Cygni

True Zen. Dist. Observed in Mr. Bryan's

field reduced to 1st Jan. 1764

Precession to 11 October 1766

1

8

O CO

o o

C*" !>

1

4

50

35. 19
+23.03

0

12

38.20
-30.75

True Zen. Dist. 11 October 1766

1

8

39.97

4

50

58. 22

0

12

07.45

Ditto Observed at the Middle Point

1

7

10. 79

6

6

46.65

1

3

40. 18

Celestial Arch between the Observatory in

Mr. Bryan's field and the Middle Point

1

15

50.76

1

15

48.43

1

15

47.63

Plane of the Sector EAST

Delta Persei

0 i M

Capella
o t M

Beta Aurigae
o t "

Castor

O '

13

7

5

2. 0

13

5

47

42. 0

15

5

3. 0

15

47

41. 0

15

4

57 27.0

15

7

33 36.5

16

5

2. 0

16

47

41.3

16

57 27.7

16

7

33 38.2

19

5

3.7

19

47

44.0

19

57 27.3

19

7

33 38.7

Mean

7

5

2.67

5

47

42.08

4

57 27.33

7

33 37.80

Aberration

-

8.61

- 3.20

- 0.60

- 3.78

Deviation

-

8. 26

- 7.52

- 6.75

+ 4. 20

Precession

-

2.26

- 0.95

- 0.29

- 1. 25

Refraction

+

7. 08

+ 5. 80

+ 4.95

+ 7.55

Mean Zen. Dist. 11th Oct. 1766
Plane East

7

4

50.62

5

47

36.21

4

57 24.64

7

33 44.52

165

1766

December

Plane of the Sector WEST

Delta

Persei

Capella

Beta Aurigae

Castor

o

i M

o

i ii

0

i ii

0

1 M

21

7

5 10.3

21

5

47 52.8

21

4

57 35.3

21

7

33 30.0

24

7

5 10.5

24

5

47 52.3

24

57 35.0

24

33 30.8

27

5 9.7

27

47 51.0

28

57 35.6

Mean

7

5 10.17

5

47 52.03

4

57 35.30

7

33 30,40

Aberration

- 9.37

- 4.24

- 1,60

- 3.52

Nutation

- 8.26

- 7.52

- 6,75

+ 4,20

Precession

- 2. 56

- 1,09

- 0.32

- 1,36

Refraction

+ 7.08

+ 5.80

+ 4.95

+ 7. 55

Mean Zen. Dist. 11 Oct. 1766

7

4 57.06

5

47 44,98

4

57 31. 58

7

33 37.27

Ditto Plane East

7

4 50.62

5

47 36.21

■;

57 24.64

7

33 44.32

True mean Zen. Dist. Oct.
the 11th 1766

True Zen. Dist. Observed at

7

4 53.84

5

47 40, 60

4

57 28.11

7

33 40,90

Brandywine in Jan. & Feb. re¬
duced to the 1st. Jan., 1764

7

4 22.2

5

47 32.3

4

57 26.3

7

33 23.1

Precession to Oct. 11, 1766

+34.61

+14.56

I

+ 4.28

+ 18.97

Reduced to Oct. 11, 1766

7

4 56.81

5

47 46.86

4

57 30. 58

7

33 42.07

True Zen. Dist. Observed in
Mr. Bryan's field reduced to
1st. Jan. 1764

Precession to 11th Oct. 1766
True Zen. Dist. 11th Oct. 1766
Ditto Observed at the Middle Point
Celestial Arch between the Ob¬
servatory in Mr. Bryan's field
and the Middle Point

Alpha Cygni

4 43 25.95

+34.59
44 00. 54
59 52. 92

1 15 52.38

Capella
6 00 26.60

+ 14. 56

6 00 41.16

7 16 29.20

1 15 48.04

(Undated)

(Undated)

After this leaf comes in the two sheets A and B - here leave one
or one leaf blank.

(Charles Mason)

63° 5' 40"6 Distance to Pole 1 Jan. 1750

- 5* 191’8 = Precession to October 11,

1766

63 c

0 * 20l‘8

i

-10"0 =

Aberration and Nutation

1

63°

O' 101*8 =

Apparent Declination of Star

26°

59' 49:'2

Alpha Ursae Majoris (Polar Distance) Pole Apparent

75°

10' 51"2

Sum Sidj

- 4' 6"1

One-half S|

pm

75°

6 ' 45'.'1

Beta Ursae Minoris (Declination)

Aberration : Nutation : 0

(log)

14°

53' 15"

Beta Ursae Minoris to the Pole

As Sine 39° 16

' 8" - 1/2 Sum 1st (Line) =

9.8013767

: Sine one-half Difference 12° 16' 18"

9.3274554

Co Tang one-half P = 85° 58' 22"

To Tang: one-half Difference Angles“1° 21' 16"
As Cos one-half Sum Sides 39° 16' 8"

Cosine one-half Difference 12° 16' 18"

Co Tang one-half Angle P 85° 58' 22"

: Tangent one-half Sum angles
one-half Difference angles
Hence

5 ° 4
, lO 21

41"

16"

8.8475990
10.1750544
8.3736777
9.8888443
9.9899616
8.8475990
18.8375606
8.9487163

264

265

For the Angle at the
Middle Point (of our
1st Line with the Meridian) by
Celestial Measurements.

51 u 32
26° 59

78 °

39°

26"

49"

15"

08"

24° 32' 37"

12 ° 16' 18" = one-
half Difference

25" = Angle Z
makes with the Meridian by Alpha Ursae Majoris

the Angle ojir first Line

51° 32' 26”
14° 53' 15"
66 ° 25' 41"
One-half 33° 12

Difference

360 39' 11"

18° 19' 35" = One-half Difference

50"

166

(Undated)

Sine
: Sine

Co-Tangent one-half angle

33° 12' 50" =

18° 19' 35" = 9.4975235 : Cosine one-half difference 18° 19’ 35” = 9.9'
one-half angle 83° 19' 11” = 9.0686461 :: Co-Tang one-half P 83° 19' 11” = jLOl

18.5661696 9. 0‘

•half Difference angle 3° 50' 47” 8. 8275745 : Tangent one-half Sum Angles 7° 34' 12” 9. 1!

-3° 50* 47”

3° 43’ 25” = Ang

Angle at the Zenith = the Angle our first Line
makes with the Meridian according to Beta
Ursae Minoris. Figures a and b

57° 42' 57"0 a’ Pole 1st Jan. 1750 of Beta Ursae Majoris
- 5' 19U1 = Precession to October 11, 1766
57° 37' 37l'9 Mean distance a' Pole on Ditto
= Aberration and Nutation

= Apparent Polar Distance 11th October 1766

For the Angle our 1st Line makes with the Meridian by Terrestrial Measure
Here M, the Middle Point, MN = 80 Chains 00 Links measured

PM . the Line . PN = 5 chains 14 feet and 0. 3 of an inch = 5 Chains 212. 5 Links, then
as NM, the Meridian = 80 Chains 00 Links (logarithm) = 1.9030900

: Rad * 10.

:: PN 5. 2125 Chains 0.7170461

Tangent angle M 3° 43' 40”5 ; 8. 8139561

9.7385951 As Cosine one-half Sum Sides 33° 12' 50" = 9.9225342

9.4975235

18° 19* 35" = 9.9773947
83° 19' 11" - 9.0686461

Tangent one-half Difference angle 3° 50’ 47” 8. 8275745

9.0460408
9. 1235066

= Angle Z or

Angle according to Alpha Ursae Majoris 3° 43' 25" )
Ditto by Beta Ursae Minoris 3° 43' 25” ;

30 43' 30” =

Celestial Measures

Latitude of the Observatory in Brandywine

Mean of theArchs by the different stars leaving out Capella

Latitude of the Middle Point

Distance of the Pole from the Middle Point

Angle our 1st Line makes with
the Meridian at the Middle Point,
390 56' 19"

2 11a 1° 28’ 45”

37° 27' 34"

52° 32' 26"

Figure

267

The Right Ascension of the Mid-Heaven of Alpha Ursae Majoris when Passing 1 Line (probably Meridii
22h 16m 53. 8s by obs. : on 12th October 176^ By daily Motion of the Clock
16m 55. Is Ditto on 13th

16m 54. 7s Ditto on 16th using the Motion of the Clock by Alpha Cygni and Beta Andromedae
22h 16m 54. 5s = Mean = 334° 13' 38"

Right Ascension of Alpha Ursae Majoris 162° 16 1 54 ” j

Angle at the Pole 171* 5 56' 44” j

Right Ascension of the Mid-Heaven when Beta Ursae Minoris passed the Line,
lh 58m 7. 8s (by observation on the 14th day using the Motion of the Clock by Alpha Cygni

and Beta Andromedae and lh 58m 9. 0s if the daily Motion of the Clock is
altered by Alpha Cygni.

by Ditto on 15th using the Clocks daily Motion =55 seconds this 24 hours.

58m 7. Is by Ditto on 16th using the Clocks Motion by Alpha Cygni and Beta Andromedae

lh 58m 7.5s = the Mean = 29° 31' 52”

Right Ascension of Beta Ursae Minoris 222° 53' 30”

Angle at the Pole 166° 38' 22"

Right Ascension of the Mid-Heaven when Beta Ursae Majoris passed the Line.

167

(Undated)

86 ° 32' = Angle CTO = the angle measured between CT and Radius from Newcastle and
TO the Meridian

93° 28' * Angle OTA, then angle ATP = TAL = 3° 28' for P in the Parallel of T, and A in the

Parallel of L. A the End of our 1st Line.
E the line extended to the Parallel of T.

(logs)

As Rad 10.

: Sine 3° 28* 8. 7815244

:: 22. 51 Chains 3.3523755

AP = TL 136. 1 links 2. 1338999

* what the end A of our 1st Line is South of the Tangent Point T,

= 81 miles 78 chains 31 links = 6558.31 chains = AM measured

(log)

Rad 10.000

:6558. 31 chains AM = 5.8167920

.. Cos 30 43’ 30” Angle M = 9.9990815

: 6544.46 chains = NM = 5.8158735
Miles Chains Links
LT = 0 1 36

TO = 5 2 43

bB = 14 56 17 = the dist. between the Observatory in Brandywine and Mr. Bryan's

Ob = 0 7 91 = Parallel Oo south of b.

19 67 87

1587. 87 Chains = Distance on a Meridian measured.

6544.46 Chains = the Tangent Line reduced to the Meridian by the Rumb or Plain Trig.
8132. 33 = Whole corresponding to 1° 28' 441*99 = Difference of the Arch

= 101 miles 52 chains 33 links

1 ° 28'
28'

47 , . , 21
44'.’91
441*40
431*98
45l , 09
441*34
1° 28' 44'.'99

Alpha Lyrae
Gamma Andromedae
Beta> Persei
Delta Persei
Beta Aurigae
Castor
= 53241*99

Celestial Arches by the different stars, between
the Observatory at Brandywine and the Middle Point.

5324.99 seconds : 8132.33 links :: 3600 seconds : 5497.92 links
5497.92 links = 68 miles 57 chains 92 links = 1°

by reducing the line MA to a Meridian by plane Trigonometry:

arise by Spherics in the Meridian MN says as (log)

As 5497.92 chains = Length of Degree = 5.7401984

: 3600" (Seconds in 1°) = 3.5563025

:: 6558.31 chains = AM = 5. 8167920

9.3730945
: 42941*34 = 3.6328961

1 ° 11' 341*34 = AM in Degrees, Minutes, etc,
And (log)

but what difference will

As 5497.92
: 3600"

= 6544. 46 MN
42851*26

= 10 11' 251*26 = MN in

5.7401984
3.5563025
5.8158735
9.3721760
3.6319776
degrees, minutes.

etc.

by the Rund (probably Rhumb) or plane Trigonomet;

Now Let Z the Zenith at the Middle Point

Figure

269

T the Zenith at the end of the Tangent line
P the Pole

Then ZP = 51° 32' 26" = Distance Pole at the Middle Point
and PT will be distance to Pole at the End Line, thus found

(log)

Cosine

3°

43'

30"

Tangent

1 °

11 *

34'.’34

: Tangent 1st Arch

1 °

11 *

25"2

Side

51°

32'

26"

Second Arch

50^

21 '

01*8

Cosine 1st Arch

1° 11' 25'.'2

Cosine TP

50° 21' l'.'O

ZP =

51° 32' 26'.'0

Difference =

1° 11' 25l'0

N by plane Trig.

1 ° 11' 25'.'26

0726

TZP 9.9990815

8.3185337
8.3176152

Cosine 9.8048841

Cosine 1° 11* 341*34 9.9999059

19.8047900
9.9999063
9.8048837

The difference between the distance of the Pole at

the point M and the Point N, consequently MN. Figure

that MN is too great in the first reduction by the rumb or plane. 270

168

(Undated) Plane Trigonometry: and for the value of this 0"26 as

As 1° or 3600." 549792 links 0l'26 : 39.71 links. Then 8132.33 Chains

0.397

8131.933 = the whole

length of the Line (in a Meridian)

corresponding to 1° 28* 44"99, hence

the length of

a Degree as

5324’.'99 : 8131.93 Chains : : 3600"

(= 1°) : 68 miles 57.65 Chains = 1°
Accounting for the error of
one Chain in the Measurement
of AM, found by a second Measurement
May 3, 1768, the Length of
a Degree is by the whole
Line = 68 miles 58 Chains 33 Links

N. B. These results are from

Chain measure. 271

6544 Chains

46

Links = Nm by plane Trigonometry

-39. 7

Links

6544 Chains

06

Links = Nm by Spherics

1

36

= TL»

402

43

= TO'

7

91

= ob

Links

1° 15' 50" 76
15' 48"43

^ 47 "63 Arches by Different stars

52"38
48" 04

1° 15' 49'.'45 Mean = 4549l'45

as 4549"45 : 6955.76 3600" 5 1°

5504 Chains 12 links - 68 miles 64 chains 12 links

This by the Middle Point and the Point (b) in
Mr. Bryan's field.

Accounting for the error of one chain found May 3rd, 1768 the

Length of a Degree is 68 miles 64 chains 91 links. 272

169

(Undated) A Degree under the Equator

0° 121224 Yards Measured

10° 121444

20 ° 121666

30° 121884

40° 122104

50° 122324

60° 122544

66 . 5° 122687 Measured 69. 7085 Miles

700 122764

80° 122984

90° 123204

Length of a Degree =68 miles 57 chains 65 links = 68. 7206 miles

(log)

68.7206 1.8370870

Cosine Latitude 39° 43' 18" = 9. 8860155

1.7231025

1° Longitude; 52.8570 miles = 52 miles 68 chains 56 links

5° * 264 miles 22 chains 80 links

-176 _ 75 76 run

to run 87 miles 27 chains 04 links according to the Sphere

Chains 0.0857

80

68 . 560

165 miles 54 chains 88 links

+ 11 _ 20 _ 88

176 miles 75 chains 76 links

Note: The greatest curvature PC in 5° of Longitude

is about 1* 30" = 1 Inch on a Scale of one-half inch to a mile.

Dr. Be vis allows at the latitude
of 15 miles South of Philadelphia
33. 989 yards to a second
(This) makes 122328 yards to a degree
= 69 miles and 858 yards.

Parallel

Lat. Philadelphia
Brandywine

39° 43 f 18'
39° 56' 29'
39° 56* 19'

Arch between Ditto and . 1° 28* 45

the Middle Point ;

Figure

273

274

170

Memoranda. The following is the difference of
the Measurements between our 1st Line (from the Middle Point
to the Tangent) and the 3rd Line (Measured by the same Hands) at
different Points in the Line.

Miles from the Our Mile Posts fall short.

Middle Point that is to the South, of the Mile

Posts in the third Line

At the Tangent
Point

0

0

2

0.5

7

6 +

10

7.5

17

16

26

25

30

10

32

6

35

3

39

2.5

41

10

45

33

49

38

50

48

55

58

60

63

65

75

70

80

75

82 +

80

80

82-

Yards that our Mile Posts
are South of those in the
third Line.

Note: In October, 1766, we measured from the 39 mile

Post to the 40th and from the 40th to 41 in our Line; and
found them right. This we did on the Chain Carriers
informing us that they doubted some error was made
about the 40th Mile Post. But it appears by the
Measurement made in 1768 that the error was one
Chain (too much) between the 42nd and 43rd Mile Posts.

1767

March

26 At Annapolis where His Excellency Horatio

Sharpe, Esquire, acquainted us the meeting last proposed
was postponed to the 28th of April next.

31 At Brandywine.

April

Left Brandywine.

8 At Philadelphia,

9 The Gentlemen Commissioners (for Pennsylvania) acquainted us,

they had not received any positive answer from

General Johnson, whether the Indians will permit us
to continue the West Line or not.

17 At Brandywine.

25 Left Ditto and went to Philadelphia. The Gentlemen Commissioners informed us the

meeting intended on the 28th instant was postponed to the 20th of May. The agreement
with the Indians not yet completed.

Left Philadelphia.

At Brandywine.

May

20 As yet there is no account arrived of the Success of

General Johnson; for which reason the meeting was postponed.

275

17

1767

May

24 Sun. Received the Following Letter from Mr. Maskelyne (with

an Ephemeris for 1767) on which I sent the Clock, belonging
to the Royal Society by four men to be carried to Wilmington
from thence by water (one of the men with it) to Philadelphia

28 The Clock safely landed at Philadelphia„

June

2 Wrote to Mr. Maskelyne and Dr. Morton, with an account of the Clock's going, etc., etc.

An Express from Sir William Johnson acquainted the Commissioners he had made an agreement
with the Indians for to let us continue the West Line.

4 At 2h 30m to 3h 00m Apparent Time, Farenheit's Thermometer : 91°. Placed on the North side
of a House in the open Air where it was placed last Writer. This years first hot day.

5 At llh 30m in the forenoon and noon, 95°; at Ih 00m P.M,, 94°; at 3h, 95°.

6 At llh 00m in the forenoon 95° and at 3:00 P.M. 95°.

7 At sunrise. Thermometer 67°, At llh AT = 93°. At 3h, P.M. 93° (AT = Apparent Time)

8 At 6 h 30m AT 80? At llh AT 85? At 4h P. M. 91? At 7h P. M. : 80?

9 At 2h P.M. 80°. The Air much altered; being very cool and pleasant.

10 At 4h 30m P.M, 90°. At 7 P.M. 80°.

11 At Philadelphia.

12 Ditto. Wrote to the Honorable Proprietors of Maryland and Pennsylvania
acquainting them we were preparing for the Westward.

14 Sun, At 2:00 P.M. Thermometer at 95°.

15 Sent 7 Men with the Telescope of the Sector

to Fort Cumberland. The rest of the Instruments etc. by a Waggon
to Mr. Miller in the Valley,

Left Brandywine and proceeded for New-Town on

Chester River in Maryland to attend the Gentlemen Commissioners.

1767 June at 2:00 P.M.

95 o The height of the Fahrenheit Thermometer hung in

94 the Shade on the North Side of a House standing on

96 a Hill, about three Miles Eastward of Mr. Harland's.

86 This is the same Thermometer as is taken account of

87 for four months past by myself. The following

89 is by Mr. Joel Bayley.

91

94

95

98.5? At 4h P. M. at 102°

Sunday 21

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

Sunday 28

Monday

Tuesday

276

172

1767 July at 2h :

P. M.

August at 2h P. M.

September

at 2h P. M.

October at 2h P. M.

1st Wednesday

88 °

1st Saturday

85°

1 st Tuesday

76 o

1st Thursday 610

Thursday

85

Sunday

90

Wednesday

79

Friday 65

Friday

77

Monday

91

Thursday

82

Sat urday

Saturday

79

Tuesday

93. 5

Friday

78

Sunday

Sunday

80

Wednesday

93. 5

Saturday

76

Monday

Monday

83

Thursday

91. 5

Sunday

78

Tuesday

Tuesday

86

Friday

97

Monday

79

Wednesday 75

Wednesday

82

Saturday

92

Tuesday

75

Thursday 76

Thursday

84

Sunday

98

Wednesday

74

Friday

Friday

91

Monday

81

Thursday

76

Saturday

Saturday

90

Tuesday

85

Friday

68

Sunday

Sunday

92

Wednesday

90

Saturday

73

Monday

Monday

89

Thursday

94

Sunday

78

Tuesday

Tuesday

86

Friday

80

Monday

56

Wednesday

Wednesday

90

Saturday

82.5

Tuesday

64

Thursday

Thursday

93

Sunday

89

Wednesday

74

Friday

Friday

90

Monday

81

Thursday

76

Saturday

Saturday

88.5

Tuesday

80

Friday

67

Sunday

Sunday

79

Wednesday

79

Saturday

70

Monday

74

Thursday

81

Sunday

77

(Missing readings

Tuesday

66

Friday

85

Monday

76

are indistinct.

Wednesday

80

Saturday

81

Tuesday

78

edge of page

Thursday

85

Sunday

82

Wednesday

81

frayed)

Friday

92

Monday

82

Thursday

64

Saturday

87

Tuesday

86 . 5

Friday

65

Sunday

86

Wednesday

88.5

Saturday

60

Monday

88

Thursday

89. 5

Sunday

68

Tuesday

89

Friday

89

Monday

72

Wednesday

90

Saturday

82

Tuesday

69

Thursday

91

Sunday

80

Wednesday

66

Friday

93

Monday

76

278

Greenwich, Feb. 24, 1767

Messrs. Mason and Dixon,

Herewith I send you, agreeable to your desire, the Nautical Almanac
of 1767: also a table for facilitating the computations of the Moon’s distance from the Sun. I
am not a little surprised at never receiving a line from you in answer to my two letters of
October and November 1765 (in which I gave you an account that the Council of Royal Society
had agreed to employ you to measure a degree of latitude in Pensilvania, and sent you my in¬
structions on that head) nor any acknowledgement of your having received the instruments I
sent you out on account of the Royal Society; t ho Mr. Mason acquainted me you had received
my letters and would write to me as soon as you received the instruments which surely must 279

have been long ago. The Council of the Royal Society have ordered that you should send the
clock home immediately as we hear it has received great damage and must be put in order
directly for the ensuing transit of Venus over the Sun. The method of finding the longitude by
observations of the moon is approved of greatly by the public and is coming into vogue; and
will, I hope, be general in a few years. I would send you Mayer's Tables, but they are not
yet completed. I hope to have them ready for publication in a short time, after which, I may
send you a copy if I know they will reach you. You have probably heard that Mr. Bird has
received 500 pounds sterling from the board of longitude for discovering his methods of con- 280

structing and dividing instruments, and making plates of the principal instruments at Greenwich,
and taking apprentice, and instructing workmen in his art. Dolland's telescopes answer sur¬
prisingly; I have one of only 3 1/2 feet long with 3 object glasses at the Observatory which
magnifies 140 times and is superior to a two foot reflector, equal to a ten foot of Dolland's with
2 object glasses, & little, if at all, inferior to the 6 foot Newtonian of the Observatory. These
will be the best telescopes for carrying abroad to observe Jupiter's satellites. I desire to hear
from you directly and to know what you are doing, or have done about the measure of the degree.

Be pleased also to send an account of your having received the instruments & what, I am

Your sincere friend & humble Servant

N. Maskelyne

281

173

(An envelope addressed)

To Messrs. Mason and Dixon
Surveyors to the Honorable William
Penn

In Pensilvania 282

Memoranda

1767

At the top of Savage Mountain very good free-stone. Opposite the 174th and 175th Mile Post about
half a mile to the Southward, there is a remarkable Quantity of the large tall Spruce Trees.

On the Little Yochio Geni, a piece of rich land about a Mile in length and a Quarter of a mile in
breadth (to the South of the Line) in which a great variety of Plants. Haws of a very large size.

Hops, wild Cherry Trees etc. etc. - it appears like - a Garden desolate.

From the top of Savage Mountain to this, is a wild waste, composed of laurel swamps, dark
vales of Pine through which I believe the Sun's rays never penetrated.

A pretty good tract of Land on the North side of the Line near the Little Yochio Geni.

On the big Yochio Geni are very good tracts of Land and the Hills very rich. About three Miles
South of the Line, I was informed there is a tract of 500Acres upland and 200 of rich Bottom near
it on the Yochio, now void. There are seven families settled on the said River within 3 Miles
of the Line. The Bottom of the Big Yochio, is of a Black, hard, round stone.

At 197 Miles 53 chains crossed a Glade (or meadow) about 10 chains wide and length to the North
seen 1/2 a Mile & to the South a Mile, but where it begins or ends I know not.

At Entered - ) a Glade

Left - J 283

At our Station where the Sector was set up on the 17th of August we were paid a visit by 13 Delawares;
one of them a Nephew of Captain Black-Jacobs, who was killed by General Armstrong at the Kittony
Town in 17 . This Nephew of Black-Jacobs was the tallest man I ever saw.

From the Station we passed over very desert, woodland Barren soil with very sudden deep bottoms,
immediately rising again nearly perpendicular. The tops of the Ridges chiefly chestnut, even to
the top of Laurel Hill.

No fish to be found in neither of the Yochio Genies nor in the Sandy Creeks, Occasioned I believe
by the great falls the waters had at leaving the Mountains, up which the fish cannot pass.

Laurel Hill (or rather Mountains), is a Wild of Wildes; the Laurel overgrown, the Rocks gaping
to swallow up, over whose deep mouths you may step. The whole a deep melancholy appearance
out of nature. But from the Summit of the Westernmost Ridge, viz. from the Point 214 miles
12 chains there is the most delightful pleasing View of the Western Plains the Eye can behold.

From hence the end of our Line may be seen, and about 10 Miles farther, which reaches a Ridge
or Ridges, that divides the Waters running into the Monaungahela from those running into the
Ohio,

This Ridge terminates the Sight and makes a beautiful Horizon that may be seen more than 100
miles from North to South.

In the Rivers Cheat and the Monaungahela, we found plenty of fish of various sorts, and very

large; particularly cat fish.-caught a Lizard near a foot in Length. Coal is found very

plenty here, and beyond the River in our Line.

About two miles west of Monaungahlea we were paid a visit by Catfish, his Nephew, and Squaw

(or wife) : They were very well dressed nearly like Europeans; and he (Catfish) being a Chief

of the Delaware Nation, our Chief held a Council and made a Speech (and presented him with

some strings of Wampom) to him; in which they acquainted them of our business there: He 284

seemed to be very well satisfied, and promised to send the strings of Wampom to his Town,

and to come again in 15 days; but he never returned.

174

1767

Six Miles beyond the River, Eight Warriors of the Seneca Nation fell in with us, in their way
to the Southward going against the Cherokees. These people go 700 Miles through these Deserts
to War. They are one of the Six Nations, which made the Indians with us, very glad to see them.

They were equipped with Blankets and Kettles, Tomahawks Guns and Bows and Arrows; they
staid two days with us, got a small supply of Powder and paint; when their Captain ordered to
march.

At our last station, among many others came Prince Prisqueetom, Brother to the King of the
Delawares; he spoke very good English; (and though his face is deeply furrowed with time, being
86) told me, his Brother and himself had a great mind to go and see the great King over the
Waters; and make a perpetual Peace with him; but was afraid he should not be sent back to his
own Country.

The land westward of the Monaungahela is very rich and fertil, Rich-Weed and Pea vine, so
thick you can scarcely get through it: which is the richest pasture for Cattle I ever saw.

The old Prince above mentioned gave a very good description of the Ohio and Mississippi,

all agreeing with others that it runs through a plain level Country, the land very good: Meadows

by nature of Miles square (having only a few Trees in them.) whose verdant plains never heard

the Milk Maid singing blithe and gay. Though, who can tell, what he has done that made them;

a Thousand annual Suns to him how short. 285

The following is a description of the Ohio and Mississippi, as described to me by Mr. Hugh
Crawford, our Interpreter, who has traversed these parts for 28 years, either as an Indian
Trader or Commander in his Majesty's Service in the late Wars.

Beginning at the Mouth of the Mississippi. The Island of New Orleans lies about 100 Miles from
the Bar of the said River.

At about 100 Miles above Orleans, on the West side comes in a River nearly as large as the
Mississippi. This River heads in the Mountains of Mexico. At the head of the said River,
the Spanyards have a fortification - 300 Miles above Orleans is Natchees. Here the French
have a Fort. This is on the East Side of the River, and one of the most beautiful places
for a Settlement nature can produce, the lands exceeding rich: the Seasons one continued Spring,

Ships of two or 300 Tons may come up the River as far as this (Natchees), and sloops of 30 Tons
up to the Forks of the Ohio. One place only he doubts is a little dubious, about 200 Miles below
the Forks, where there is 20 or thirty small Islands, but he Judges the Navigation is good on the
West Side of the Islands, but had not time to prove it.

The River Mississippi is in general about half a Mile in breadth, and by the French account
1360 Miles in Length from the Forks of the Ohio to the Mouth (in the bay of Florida) .... this
length he supposes to be very near.

There are many fine River falls into the Mississippi between the Natchees and the Forks of the
Ohio from both Sides, which are but very little known therefore shall leave them; but must observe
the whole is a plain rich land.

The Ohio at the Forks is very near as large as the Mississippi. From the Forks on a due North
Course 140 Miles up the Mississippi, lies the Country called the Illinoies; first settled by the
French, who were encouraged by the French King to marry with the Indians. Each couple re¬
ceiving a premium of 50 pounds provided the Native embraced the Catholic faith. By this means
it soon became a fine settlement, and here the French erected a Fort; called it Fort Sharter
but the Fort and Country being on the East Side of the Mississippi it fell into the Hands of the
English by the Treaty of Peace in 176_ and his Britanic Majesty has now a Garison in the 286

said Fort - Sharter.

The Mississippi North of the Illinois is but little known, its banks are settled by the Indians, who
have had very little (and some not any) correspondence with the Europeans.

Therefore returning again to the Forks of the Ohio, and taking its course up, we find many RiverSj
on both sides emptying into it, all of which my informer has been up and down for many Miles.

The land in the forks of the Mississippi is very good. Here it is much to be wished there was a
Settlement. The climate and the Soil inviting every Stranger's Stay. About 50 Miles up the Ohio
the French erected a Fort called Desumption, from hence by land to the Illinois about 70 Miles.

175

1767

(See date
below)

On the East side of the Ohio from its mouth up to Pits burg (called by the French Fort du Quesne)
comes in the Rivers Cherokee, Broad River, Kentucke, Great Salt Lick, Totteroy, Great
Kanhawa. These all head in the Allegany Chain of Mountains.

The Mouth of the Cherokee River is about 60 Miles above the Forks. 15 Miles above this comes
in Broad River. The length of the Cherokee River (is) about 400 Miles running through level
country. Broad River for 200 Miles in length may be walked over in the summer, being not above
two feet deep - smooth level bottom, and breadth in general one mile and a half!

Above the Great Kanhawa is little Kanhawa, near the head of which is the End of the West Line
where we left off. Above the little Kanhawa is Fishing Creek and the two Weeling Creeks, which
is all of note to Pitsburg.

On the West side of the Ohio comes in the Rivers (beginning at the forks), Wabash, Mineami
(Rocky River), Siota, Kockhocking, Muskingum; and Beaver Creek near to Pitsburg. These
all Head in Lowlands near Lake Erie, interlocking with the heads of short creeks, which runs
Northward into the said Lake.

The Mouth of the Wabash River is about 150 miles above the forks. It runs through a beautiful
Country, if a Desart of rich level land may be called so, where the Meadow bounds are scarcely
within the limits of the Eye. Mineami (or Rocky River) the Great, (for there is a lesser between
this and Siota) is very rapid, and the West branch heads very near a River of the same name
that runs in to the South West end of Lake Erie.

Siota is very gentle, its Banks and the Ohio about its Mouth; is the Seat of the Shawanes and
Delaware Indians, who live here by the leave of the Six Nations.

Muskingum, all gentle to the Head, whence to the head of Cayaga River is but about one mile
over which the Indians often carry their Canoes, and down Cayaga in to Lake Erie. Upon these
Rivers lives the Mingoes, Tuscarawas, etc. The Tuscarawas Ancient seat was in Virginia,
where they have now some of their friends living. Their King with a few attendants I saw at
King-William's Court House in Virginia; in March 1766, who were going to pay a visit to their
Brothers.

The head of the Allegany River is about 200 Miles NE from Pitsburg and runs down on the
West Side of the Allegany Mountains, through a plain, inferior for the richness of its soil to
none; at Pitsburg it is joined by the Manaungahela and is afterwards called the Ohio.

From Pitsburg to the Forks where the Ohio falls into the Mississippi is about_Miles.

From the End of our line to the Ohio on a West Course is about forty miles, on a Northwest
Course about 30 Miles. The West Line that divides the Provinces of Maryland and Pennsylvania
if Extended would fall on the Ohio about the mouth of Fishing Creek. From here a West Course
would pass through the Southern part of the Illinois. The distance about 7 or 800 Miles.

A country says my informer, through which you may travel 100 Miles, and not find one Hill,
or one Acre of barren Land.

In this large tract of Land all lies waste except just on the banks of the Rivers, where the Natives
in general resort.

Gentlemen:

You are to repair immediately to the Place on the West Line where you left off last fall,
and continue that Line in the Manner heretofore directed, to the End of Five Degrees of Longitude
from the River Delaware, in the Parallel of the said West Line; after which you are as you return
to have a Visto opened between the several Posts that may be fixed in the said due West Line so
that the said Line may be described and distinguished by one continued Visto, according to your
former Instructions; Or, if you find that time can be saved by employing your Workmen in opening
the said Visto, while you are taking Observations in order to correct your Deviations in proceeding
with the said West Line, you are desired so to do.

While you are opening the Visto which is to describe the West Line or Parallel of Lati¬
tude, you are to set up a Post on the Summit of every Ridge over which the said West Line shall
pass in the Direction of the said Line: You are likewise to heap Stones around the said Posts
(where Stones may be very near and easily raised) so as that the same may be visible from Ridge
to Ridge for the better ascertaining the Place where the West Line passes every Ridge.

289

176

(See date You are also to send proper Persons to Baltimore Town in Maryland where there are

below) one hundred and thirty nine Boundary Stones that they may convey the said stones to the proper
Places in the West Line, which Stones you are to set up in the said Line as you return, in the
same Manner as the other Boundary Stones have been fixed. But if it should happen that the
Places, where any of the said Boundary Stones ought to be fixed are on the Tops of high Mountains
to which the said Stones cannot be carried, you are in such Places to erect and heap up together
large Quantities or Piles of Stones to ascertain, mark and perpetuate the said Spots or Places 290

taking particular Notice thereof in your Minute Books and report the same to the Commissioners
at their next Meeting.

As soon as you have extended the Line to the End of Five Degrees of Longitude you are
to give immediate Advice thereof to the Commissioners that they may give Notice to each other
and appoint another Meeting.

A Number of the Indians have been deputed by the Six Nations (whose Consent hath been
obtained to our extending the West Line to the Western Limits of the Province of Pennsylvania)
to be present at, and attend you in running the said Line, and Orders have been given for them to
meet you at York town in Pennsylvania: As the public Peace and your own Security may greatly
depend on the good Usage and kind Treatment of these Deputies, we commit them to your particular
Care, and recommend it to you in the most earnest Manner not only to use them well yourselves
but to be careful that they receive no Abuse or ill treatment from the Men you may employ in
carrying on the said Work, and to do your utmost to protect them from the Insults of all other per¬
sons whatsoever.

Chester Town 18th June 1767

Horatio Sharpe
John Barclay

Dan of St. Thomas Jenifer
J. Beale Bordley

To Messrs Charles Mason
& Jeremiah Dixon

Benjamin Chew
Edward Shippen, Jr.
Thomas Willing

Chester Town 18th June 1767

The Commissioners recommend to Messrs Mason and Dixon That the spirituous
Liquors to be given to the Indians attending them, be in small quantities mixed
with water and delivered to them not more than three times every day.

Horatio Sharpe Benjamin Chew

John Barclay Edward Shippen,

Dan of St. Thomas Jenifer Thomas Willing

J. Beale Bordley

The Proprietors' Journal for 1767, as follows,

Jr.

nearly

292

1767
March
22 Sun.

June

3

12

15

17

18

Left Brandywine and proceeded to Newtown on Chester River to attend the

Gentlemen Commissioners on the 24th Instant according to their appointment in November last.

At Chester Town. The Commissioners not being come, we set out for Annapolis.

At Annapolis where we were informed by his Excellency

Horatio Sharpe, Esquire: that the meeting intended the 24th was postponed

to the 28th of April next, on account of the Commissioners not receiving any certain

intelligence of Sir William Johnson's having agreed with the Natives for us to

Continue the West Line.

Were informed that an agreement was concluded with the

Six Nations for us to proceed with the West Line, and that the Gentlemen Commissioners were to
meet at Chester Town the 16th Instant.

Wrote to the Honorable Proprietors of Maryland and Pennsylvania.

Sent seven Men with the Telescope and the Sector to the Allegany Mountain where we left
off last Summer

Attended the Gentlemen Commissioners at Chester Town.

Attended Ditto and received our Instructions to proceed with the West
Line to the End of 5 degrees of Longitude from the River Delaware.

177

1767

July

7 The Waggons arrived at Fort Cumberland with the Instruments, Tents, etc.

Lodged with Colonel Crisep near the Forks of Potowmack; he has here a most beautiful
Estate. This is the same Gentleman mentioned in Journal of the 17th of January 1765.

8 At the Allegany Mountain; where we left off last Summer.

Placed a mark Eastward in a direction from the Post we left off at in the true

Parallel; to be again in the true Parallel at 10' West. 293

(Undated) Thus

Let O(be) the Post we left
off at. p another point
in the true Parallel East of 0
Then the Angle DOC = 8’ 18" for

Angle NOP = 89° 55' 51" when the Chords NOand OQ = 10 minutes as usual
4

359° 43‘ 24" = four times the angle
Complement = 16' 36" = the two angles A O B and DOC

One half = 8* 18" = angle DOC and A © B, which with the measured distance

= Op = OC=l mile 78 chains, we have DC thus;

as 40 chains : 9. 6575 links :: 158 chains (= 1 mile 78 chains) : 38. 14 links = DC
38. 14 links = DC

17. 00 links = Dp = distance of the chord from the circle at the distance of 1 mile 78 chains from O
21. 14 = pC * The distance to be laid off from p to C to give the chord ON

Note: The Post at O left off at in the true Parallel » 165 miles 55- chains

Mark or Station at C at the top of the little Allegany = 163 miles 57 chains

Radius = 1 mile 78 chains

July

11 Widening the Visto to the Eastward to see the Mark in the said Direction.

12 Sunday

13 Began in the true Parallel and continued the Line Westward
in the above mentioned Direction.

Continued the Line.

At 168 miles 78 chains the Top of Savage Mountain or
the great dividing Ridge of the Allegany Mountains.

Continued the Line.

At 169 miles 60 chains crossed a small run or branch of the
little Yochio Geni. The Head of Savage River to the
South about one Mile.

16 Continued the Line. This day we were joined with

14 Indians, viz. Mohawks and Onondagas sent by the Six Nations

to conduct us through their country, namely three Onondagas * Figure

and eleven Mohawks. (With them came Mr. Hugh Crawford, Interpreter.) 294

17 Continued the Line.

18 Continued the Line.

At 171 miles 5 chains crossed Ditto run or a second Branch of the Little Yochio.

At 171 miles 63 chains crossed this branch the last time. In the whole about 6 or 7 times

19 Sunday

20 Continued the Line.

Continued the Line.

At 173 miles 1 chain crossed a small run running Northward.

22 Continued the Line *

23 Continued the Line.

24 Continued the Line.

At 176 miles 15 chains crossed a large branch of the Little Yochio.

Continued the Line. '

At 177 Miles 4 Chains 45 Links changed the direction to be in the

true Parallel at 10 1 West: There we measured a Radius

of 58 Chains, and as we began in the true Parallel the angle is 8‘ 18"

as usual which 40 chains gives 9. 6575 Links, then

as 40 : 9. 655 :: 58:14 Links which we laid off to the Northward

for 177 miles 4 chains 45 links = change

Station 177_62_ 45

58 00 = Radius

At 177 Miles 39 Chains crossed the Little Meadow riin, running in to the Little Yochio Geni.

26 Sunday

27 Continued the Line. At 178 Miles the Little Meadow South, distant about 2. 5 Miles. 295

178

1767

July

28 Continued the Line.

At 179 miles 44 chains Crossed the Little Yochio Geni.

29 Continued the Line.

30 Continued the Line.

At 182 miles 38 chains crossed a small Branch, running into the
Little Yochio v

31 Continued the Line,

August

1 Continued the Line.

At 184 Miles 13 chains, The top of little Laurel Hill.

2 Sunday

3 Continued the Line.

At 185 miles 7 chains crossed a small run.

4 Continued the Line.

5 Continued the Line*

(186 miles 2 chains j

At <186 miles 38 chains > Crossed small runs.

Il87 miles 20 chains)

6 Continued the Line.

At 188 Miles 41 Chains 65 Links Changed our direction to be in the true

Parallel at 10' West. Thus

next Station 188 _69_ 50

Radius = 0 27 85 And as we began in the true Parallel

the angle is 8’ 18" as usual which at 40 chains radius gives

9. 6575 Links, then as 40 : 9.6575 :: 27. 85 : 6,7 Links, this we laid

off to the North at 188 Miles 69 Chains 50 Links and continued the Line as follows.

7 Continued the Line in the direction changed.

At 189 Miles 57 Chains. The top of Winding Hill.

189 Miles 69 Chains crossed General Bradock's Road leading
from Fort Cumberland to Fort Pit.

190 Miles 1 Chain crossed Ditto a second time.

8 Continued the Line.

At 190 miles 34 chains crossed the above road a third time.

191 miles 69 chains crossed a small run.

9 Sunday

10 Continued the Line.

11 Continued the Line,

At 194 Miles 25 Chains 25 Links the East Bank of the big Yochio Geni.

194 Miles 28 Chains 00 Links the Middle of a small Island, about 200 yards wide
194 Miles 31 Chains 65 Links the West Bank of the river. The water
about a foot deep.

12 Continued the Line.

At 196 Miles 31 Chains crossed a small run.

13 Continued the Line.

At 197 Miles 53 Chains crossed a small run passing through a Glade.

198 Miles 5 Chains crossed a small run.

14 Continued the Line.

At 198 Miles 69 Chains the top of the ridge that divides the

waters of the Yochio Geni from the waters
of Sandy Creek, which runs into
Cheat River.

15 Continued the Line.

At 199 Miles 33 Chains crossed a small run, running into Sandy Creek

16 Sun. Sent for the Sector, etc. From Mr. Spears's at the

crossing of the Yochio Geni on Braddock's Road.

17Q

1767

August

17

17

18

19

20

20

Set up the Sector in the direction of our Line
at the distance of 199 Miles 63 Chains 68 Links from the Post
marked West in Mr. Bryan's field and made the
following Observations.

Plane EAST

Star Name

Nearest Point

Revolutions

Difference

Apparent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

o

i

R

n

i

it

o

i

it

Capella

6

0+

7

36

0

27

6

0

27.0

7

9

Alpha Lyrae

1

10-

7

4

1

27.5

1

8

32. 5

5

20.5

Delta Cygni

4

50+

3

51+

1

2.6

4

51

2

41-

Gamma Cygni

0

10+

9

18-

1

58.3

0

11

58.3

11

32

Gamma Cygni

0

15-

9

18-

3

4.2

0

11

5

41.5

Alpha Cygni

4

45-

7

39

0

o

oa

m

4

44

8

39

Capella

6

0+

10

40.5

0

24.8

6

0

10

16-

Alpha Lyrae

1

10-

6

17.5

1

27.2

1

8

4

34+

Delta Cygni

4

50+

4

18

1

4. 7

4

51

4.7

3

5+

Gamma Cygni

4

45-

4

19.5

(Not reduced)

5

12. 5

Capella

6

0+

9

4-

0

26.2

6

0

8

29. 5

Alpha Lyrae

1

10-

9

32

1

28. 0

1

8

7

48

Delta Cygni

4

50+

6

46+

1

2.3

4

51

2.3

5

36

Gamma Cygni

0

10+

8

30. 5

1

56.5

0

10

43

Alpha Cygni

4

45-

9

19.5

0

52.0

4

44

8.0

10

19.5

After we had made the last Observation we

turned the Instrument

298

Plane WEST

23 Sun.

Capella

6

0

8

39+

0

35.4

6

0

35.4

9

23-

Alpha Lyrae

1

10-

8

33-

1

31.6

8

28.4

10

20+

Delta Cygni

4

50+

10

35+

1

10.7

4

51

12

2

Gamma Cygni

0

10+

11

27

1

53.0

0

11

53.0

9

18

Alpha Cygni

4

45-

9

39.5

0

47.5

4

44

12.5

8

44

Alpha Lyrae

1

10-

5

42. 5

1

34.0

8

26.0

7

32.5

Delta Cygni

4

50+

7

37+

1

11. 0

4

51

11.0

9

4+

Gamma Cygni

0

10+

9

13.5

1

52.8

0

11

52.8

7

5-

Alpha Cygni

4

45-

5

41-

0

45.7

4

44

14.3

4

47

Cloudy.

Computing our Observations etc.

as follows.

299

180

1767

August

17

18

19

20

Plane EAST

20

21

22

Alpha Lyrae

Delta Cygni

Gamma Cygni

Alpha Cygni

Cape 11a

o

i

ii

o

1 «

0

1 "

o

i

ii

o

i «»

6

0 27.0

1

8

32.5

4

51 2.6

0

11 58.3

4

44

8.0

6

0 24.8

32.8

6

0 26.2

32.0

51 2.3

11 56.5

44

8.0

Mean 19d

1

8

32.43

4

51 2.45

0

11 57.40

4

44

8.0

6

0 26.0

Aberration

+ 13. 86

-11.46

+ 9.47

- 8.45

+ 7.97

Deviation

- 3.75

+ 1.63

- 0.40

- 0.23

- 6.05

Precession

+ 9. 14

-30.03

+40.30

-45. 14

-19.19

Refraction

+ 1.20

+ 5.60

+ 0.20

+ 5.50

+ 7.00

Mean Zen. (Dist.)

1

8

52.88

4

50 28. 19

0

12 46.97

4

43

19.68

6

0 15.73

1st Jan. 1764

Plane WEST

6

0 35.4

1

8

28.4

4

51 10.7

0

11 53.0

4

44

12,5

8

26.0

4

51 11.0

0

11 52,8

4

44

14.3

(Mean)

1

8

27.20

4

51 10.85

0

11 52,90

4

44

13,40

6

0 35,4

Aberration

+14.35

-11.92

+ 10,08

- 9. 11

+ 7,95

Deviation

- 3., 75

+ 1.63

- 0,40

- 0,23

- 6. 05

Precession

+ 9.14

-30. 03

+40.30

-45.14

-19.19

Refraction

+ 1.20

+ 5.60

+ 0,20

+ 5. 50

+ 7.00

1

8

46. 14

4

50 36.13

“'6

12 43.08

4

43

24.42

6

0 25. 11

52. 68

28. 19

46.97

19.68

15.73

True Zen. Dist.

1

8

50.51

4

50 32. 16

0

12 45.02

43

22. 05

6

0 20-42

Ditto at Post

1

8

41.80

4

50 40.40

0

12 33.00

4

43

31. 20

6

0 31.80

Marked West

Offset

South 8. 71

South 8.24

South 12.02

South 9. 15

South 11,38

8. 24

1 9 H9

11.38

(Mean) 9.9 =15 chains 00 links to be laid off to the Southward.

300

181

1767

August

changed

Undated

Miles from the Post

Offsets from

Offsets from

True

Marked West

the Circle

the Triangle

Offsets

in Mr. Bryan's Field

Chains

Links

Chains

Links

Chains

165.68

0

00

0

00

0.00

Sector

166

0

02

0

14

0. 16

167

0

11

0

57

0.68

168

0

18

1

00

1. 18

169

0

23

1

46

1.69

170

0

25

1

90

2. 15

171

0

27

2

34

2.61

172

0

27

2

76

3.03

173

0

26

3

22

3.48

174

0

23

3

65

3.88

175

0

18

4

08

4.26

176

0

12

4

52

4.64

177

0

03

4

97

5. 00

178

0

0

5

48

5.48

179

0

08

5

92

6.00

180

0

15

6

34

6.49

181

0

23

6

73

6.96

182

0

25

7

16

7.41

183

0

27

7

61

7.88

184

0

27

8

05

8.32

185

0

26

8

49

8.75

186

0

23

8

93

9. 16

187

0

18

9

37

9.55

188

0

06

9

81

9.87

188 miles 41 ch. 65 links

0

189

0

05

10

25

10.30

190

0

14

10

69

10. 83

191

0

21

11

13

11.34

192

0

25

11

58

11. 83

193

0

27

12

02

12. 29

194

0

27

12

46

12.73

195

0

26

12

90

13. 16

196

0

24

13

34

13. 58

At this Station (199. 78) Mr.

197

0

20

13

78

13.98

John Green, one of the Chiefs of

198

0

14

14

22

14.36

the Mohawk Nation, and his

199

0

06

14

65

14.71

Nephew left us, in order to re¬

199 miles 63 ch. 68 links

0

0

15

00

15.00

turn to their own Country.

198 miles 69 ch. 00 links (Last Station)

Here ABCD, the true Parallel. A the point we left off at, at the foot of

Savage Mountain in 1766; where we began in 1767. The points E and F, similar to B and C
the points of changing the direction to the Northward, each an angle of 8* 18".

AEFG the Line run instead of the true chords Abed.

G the point where the Sector was set up on the 17th of August, where by the Observations,

GD (or Gd) = 15 chains 00 links = the greatest offset. Hence the Offsets to the Chords

Abed are in proportion to the distance from the point A, as according to the Triangular Column B,

to which add the offsets of the Circle from the Chords gives the true offsets south as by the Figure

Column C. (See page 301). 302

182

1767

August

25 Began to open a Visto Eastward in the true Parallel
and appointed Hands to continue it to where we
began at Savage Mountain.

26 Began in the true Parallel to continue the
Line Westward. Found the direction as

on the 19th of July thus. The Radius to the Eastward

was = 70 chains 76 links. Then as 40 chains : 9.6 links :: 70.76 chains : 16.98 links

The Chord from the Circle 10. 98 links
Rest 6. 00 links

This (6 links) we laid off to the Southward from the

Point in the Parallel 70 chains 76 links to the Eastward of the Instrument;
and proceeded in this direction as follows.

27 Continued the Line.

At 200 Miles

17 Chains Entered a Glade or Meadow.

200

21

Crossed a Run, Running North.

200

30

Left the above Glade,

201

10

Entered the same Glade a second time.

201

21

Crossed a Run running North.

201

29

Left the Glade. This Glade

is very large both to the North and South of the Line.

28 Continued the Line.

29 Continued the Line.

30 Sun. Continued the Line.

31 Continued the Line.

At)204 Miles 11 Chains) crossed small Rims, running South..

)205 Miles 60 Chains)

At 204 Mile Post the Big Meadows by information
are North, distant about 5 Miles.

September

1 Continued the Line.

At 206 miles 56 chains Crossed little Sandy Creek, about
20 yards in breadth.

2 Continued the Line.

At 208 miles 59 chains Crossed big Sandy Creek — about 30
yards wide. Both these creeks
run Southward.

3 Continued the Line.

Between 209 miles 63 chains and 210 miles 13 chains crossed a
Small run 5 times; the last time running Southward: At
the last time of crossing this Run viz. at 210 miles 13 chains we
Entered the foot of Laurel Hill.

Continued the Line.

At 211 miles 13 chains 28 links. Changed our direction to be again in the
true Parallel at 10 minutes West. Thus at 32 chains 00 links Eastward of the
point (for we could not see the point itself, it being in a deep bottom) we laid off
7. 7 links to the Southward which corresponds to the usual angle of 8 1 18"
at the distance of 40 chains and here placed a Mark. And at 212 miles
28 chains 92 links which gives a Radius of 1 mile 15 chains 64 links
we laid off 22. 95 links to the North (which corresponds to the angle 8' 18")
and from this point and the last mentioned Mark we continued the Line as follows.
At 211 miles 30 chains Crossed a small run running South.

5 Continued the Line.

6 Sunday

7 Continued the Line.

At 212 miles 61 chains Crossed a Small run, running South.

212 miles 77 chains The Head of a large Spring.

8 Continued the Line.

At 214 miles 12 chains. The top of the highest ridge of
Laurel Hill in the Line.

303

304

183

1767

September

9 Continued the Line.

At 116 miles 32 chains Crossed McCuHoch's Creek running Northerly.

10 Continued the Line.

At 217 miles 13 chains Crossed the above Creek a second time,
this is at the foot of Laurel Hill on the West Side.

At 217 miles 51 chains Crossed the above Creek a third time.

11 Continued the Line.

At 218 miles 31 chains Crossed the above mentioned Creek a 4th time, running Southward.

12 Continued the Line*

At 219 miles 22 chains 25 links The East Bank of the River
Cheat and at 219 miles 34 chains 50 links The West Bank of the
said River. We crossed the River

obliquely, but at Right Angles it is about Ten
Chains in breadth, having very level smooth bottom.

The water at present very low and is contained
in some places where it pretty freely runs; in about
20 yards wide and about two feet deep.

Here two of the Mohawks made an objection against

our passing the River, but a Council being called, the Chiefs

determined we should pass.

13 Sunday

14 Continued the Line.

15 Continued the Line.

16 Continued the Line.

At 221 miles 00 chains and at 222 miles 09 chains crossed small runs now nearly dry, 305

17 \ Brought the Sector from our last Station.

18/

19 Set up the Sector in the Direction of our
Line at the distance of 222 miles 24 chains 12 links from the
Post marked West in Mr. Bryan's field and made
the following Observations.

N. B. This Point is the top of a very high steep Bank; at the foot of
which is the River Monaungahela.

Plane EAST

Star Name Nearest Point Revolutions Difference

on the Sector and Seconds on

the Micrometer

O I R >t | II

Delta Cygni 0 10+ 5 48.5 1 37.5

7 42

Cape 11a 6 0+ 7 23+ 0 42.0

_ 6 33+ _

20 Sun. Alpha Lyrae I 10^ 7 1775 1 46.0

5 15.5

Delta Cygni 4 50+ 5 49 1 21.5

4 19.5

Gamma Cygni 0 10+ 5 22+ 1 36.2

7 14.5

Alpha Cygni 4 45- 8 30.5 0 29.2

9 8-

Capella 6 0+ 7 ’ 10 0 41.0

_ 6 _ 21 __

Alpha Lyrae I 10^ 12 23 I 47.0

10 20

Delta Cygni 4 50+ 10 30+ 1 23.3

8 51

Gamma Cygni 0 10+ 5 38- 1 36.6

7 30+

Alpha Cygni 4 45- 8 37- 0 27.8

9 12.5

After these Observations we immediately turned the Sector Plane WEST
Capella 6 0+ 5 *49+ 0 49.0

6 46+

Apparent
Zenith Distance

o » »»

i 0 11 37.5

6 0 42.0

1 8 1470

4 51 21.5

0 11 36.2

4 44 30.8

6 00 41.0

I 8 1370

4 51 23.3

0 11 36.6

4 44 32.2

6 00 49.0

306

184

1767

September

22

23

26

27 Sun.

20 Sun.

Star Name

Nearest Point

Revolutions

Difference

Apparent

on the Sector

and Seconds on

Zenith Distance

the Micrometer

0

i

R

ir

i

11

0

r

n

Alpha Lyrae

1

10

7

10.5

I

53.0

1

8

7.0

9

19. 5

Delta Cygni

4

50+

8

51

1

28. 0

4

51

28. 0

10

35

Gamma Cygni

0

10+

10

47+

l

32. 3

0

11

32. 3

9

7

Alpha Cygni

4

45*

7

30+

0

25.3

4

44

34. 7

7

5

Capella

6

0+

2

45+

0

49.2

0

0

49. 2

3

42. 5

Alpha Lyrae

1

10-

3

19-

0

49.3

1

8

10, 7

5

24

Capella

6

0

5

40. 5

0

49.5

6

0

49 . K

6

38

Cloudy

Alpha Lyrae

1

10-

5

9

1

52.0

1

8

8.0

7

17

Delta Cygni

4

50+

7

13.5

1

29.5

4

51

29. 5

8

51

Gamma Cygni

0

10+

8

23.5

1

31. 5

0

11

31. 5

6

36

Alpha Cygni

4

45-

5

28. 5

0

28.0

4

44

32.0

5

0.5

Alpha Lyrae

1

10-

7

50-

1

50.0

1

8

10.0

10

4-

Delta Cygni

4

50+

10

7

1

29.0

4

51

29.0

11

44

Gamma Cygni

0

10+

7

22+

1

31. 8

0

11

31. 8

5

34.5

Alpha Cygni

4

45-

4

34.5

0

24. 8

4

44

35. 2

4

10-

Computing our Observations as follows. 307

Plane EAST

Alpha Lyrae

O l "

Delta Cygni

O 1 "

Gamma Cygni

O » "

Alpha Cygni

O I "

Capella

O l "

19

19

0

11 37.5

19

6

0 42.0

20

1

8 14

20

4

51 21.5

20

0

11 36.2

20

4

44 30.8

20

6

0 41.0

21

1

8 13.0

21

4

51 23.3

21

11 36.6

21

4

44 32.2

Mean

1

8 13.50

4

51 22.40

0

11 36.77

4

44 31.50

6

0 41.50

Aberration

+ 17.48

-17.20

+15.63

-15.51

+ 7. 18

Deviation

Precession

Refraction

- 3. 51
+ 9.38
+ 1.20

+ 1.40
-30.90
+ 5.60

- 0.21
+41.35
+ 0.20

- 0.46
-46.30
+ 5.50

- 5.82
-19.67
+ 7.00

Mean Zen. Dist.

1

8 38.05

4

50 41.30

0

12 33.74

4

43 34.73

6

0 30.19

Plane East

185

1767

September

(Undated)

Plane WEST

Alpha Lyrae

0 t "

Delta Cygni
o I "

Gamma Cygni

O 1 H

Alpha Cygni

O i »

Capella

O 1 "

21

21

21

21

21

6

0

49. 0

22

1

8

7.0

22

4

51

28.0

22

0

11

32. 3

22

4

44

34. 7

22

0

49.2

23

8

10.7

23

23

23

23

0

49. 5

25

8

8.0

25

51

29. 5

25

11

31. 5

25

44

32. 0

25

26

8

10.0

26

~

51

29.0

26

11

31. 8

26

44

35. 2

26

Mean

T

8

8. 92

51

28.83

"T

11

31. 87

T

44

33.97

~6~

~o

49.23

Aberration

+ 17.57

-17.65

+16.16

-16.07

+ 7.02

Deviation

• 3.51

+ 1.40

- 0.21

- 0.46

- 5.82

Precession

+ 9.40

-30.96

+41.42

-46.40

-19.72

Refraction

+ 1.20

+ 5.60

+ 0.20

+ 5.50

+ 7.00

Mean Zen. Dist.

T

8

33. 58

~T

50

47.22

T

12

29.44

_

43

36. 54

~6~

T

37,71

Plane West

Ditto Plane East

l

8

38.05

4

50

41.30

0

12

33.74

4

43

34.73

6

0

30. 19

Mean Zen. Dist

l

8

35. 82

4

50

44. 26

0

12

31. 59

4

43

35.63

6

0

33.95

1st Jan. 1764
Ditto at the Post
Marked West

l

8

41. 80

50

40.40

12

33. 00

31. 20

31.80

Difference too much

51*98

3 "86

1741

41*43

2715

South

North

North

North

North

North

5798
3. 86
1.41
4.43
2. 15

Mean » 17783 t 5 = 3757 = 5 ch. 41 links that we are
to the South of the true Parallel.

308

Offsets to be laid off to the Northward

Miles from the Post

Offsets

Triangle

True Offsets

marked West

of the Circle

B

C

to the Chord

Chains

Links

Chains

Links

Links

199.796

0

0

0

0

0

200

3

0

6-

0

3

201

13

0

3

0

17

202

20

0

54

0

34

203

24

0

78

0

54

204

26

1

2

0

76

205

27

1

26

0

99

206

27

1

50

1

23

207

27

1

74

1

47

208

25

1

98

1

73

209

20

2

22

2

02

210

13

2

46

2

33

211

3

2

70

2

67

211 miles 13 ch. 28 links

0

-

--

-

--

212

7

2

94

2

87

213

15

3

18

3

03

214

21

3

42

3

21

215

24

3

66

3

42

216

26

3

90

3

64

217

27

4

14

3

87

218

27

4

38

4

11

219

25

4

62

4

37

220

21

4

86

4

65

221

15

5

10

4

95

222

5

5

34

5

29

222.301

0

5

41

5

41

■- Change

Sector

309

186

Here AcD the true Parallel. A a point in the true Parallel where
we began the 26th of August. ABC the Line run instead of the Chords
Ab and bD. C the point the Sector was set up at on the 19th of

September; where according to Observations DC -.5 chains 41 links = the greatest offset

Hence the offsets from ABC to the Chords Ab, bD (the change at b of 8* 18"

being made at its proper place viz. at 11. 37 miles from A) are in proportion to the

distances from A, as by Column B from which subtract the offsets from Figure

the Chord to the Circle, gives the true offsets North, as by Column C. 310

1767

September

28 Began to open a Visto to the Eastward in the

true Parallel to gain a Direction Westward.

Twenty-six of our Men left us; they would not
pass the River for fear of the Shawanes and Delaware
Indians. But we prevailed upon 15 ax men to proceed
with us, and with them we continued the Line Westward
in a direction found as on July 10th and the 26th of August
thus.

30 Continued the Line.

At 222 miles 34 chains 50 links the East Bank of the River Monaungahela.

222 miles 40 chains 25 links the West Bank of Ditto.

The Line crosses this River a little to the Southward of

a Right Angle to the River. The Breadth at Right Angles about 5 chains, the
Running water very low, and might be contained in the space
of about five Yards wide and Six Inches deep.

At 222 miles 74 chains crossed a Small run, running South.

October

Continued the Line.

Continued the Line. Sent a Man to set Stones on the Line, etc
and to send us hands from Fort Cumberland.

At 224 miles 5 chains Crossed the above run,

224 miles 25 chains Crossed Ditto a 3rd time.

3 Continued the Line.

4 Sunday

5 Continued the Line.

6 Continued the Line,

At /227 miles 2 chains ^Crossed small runs, running South.

1227 miles 77 chains)

Continued the Line. We have now our
usual complement of Hands,

8 Continued the Line.

At 230 miles 22 chains Crossed a small run, running Northerly.

At 230 miles 36 chains Crossed a small run, running Ditto.

Continued the Line to a High ridge. At 231 miles 20 chains Crossed a War Pati

At 231 miles 71 chains Dunchard Creek. This Creek takes its

name from a small town settled by the Dunchards

near the Mouth of this Creek on the Monaungahela; about 7 or 8

Miles North of where we crossed the said River. The

Town was burnt, and most of the Inhabitants killed by the Indians in 1755.

At 232 miles 43 chains crossed Dunchard's Creek a second time.

At 232 miles 74 chains crossed Ditto a third time.

This day the Chief of the Indians which joined us on the 16th of July informed us

that the above mentioned War Path was the extent

of his commission from the Chiefs of the Six Nations

that he should go with us, with the Line; and that he would not

proceed one step farther Westward. 312

10 The Indians with us still persisting that they

will not go any farther Westward with the Line; we
sent for the Sector which was left at our Store
House at the Forks of Cheat and Monaungahela.

11 Sun. Set up the Sector in the Direction of our Line

at the distance of 233 Miles 13 Chains and 68 Links
from the Post marked West in Mr. Bryan’s Field, and
made the following Observations.

187

1767

October

11

12

14

15

16

17

18 Sun.

Star Name

Cape 11a

Nearest Point
on the Sector

O f

6 0+

Plane EAST

Revolutions and
and Seconds on
the Micrometer

R "

6 15

5 22.5

Difference

i ii

0 44.5

Apparent

Zenith Distance

O l 'I

6 0 44.5

Alpha Lyrae

1

10-

8

17

1

45.5

1

8

14.5

6

15. 5

Delta Cygni

4

50+

5

50.5

1

23,0

4

51

23.0

4

19.5

Gamma Cygni

0

10+

6

2

1

34.3

0

11

34.3

7

44+

Alpha Cygni

4

45-

9

48+

0

26.0

4

44

34.0

10

22+

Cape 11a

6

0+

1

13-

0

41.4

6

0

41.4

0

23+

Sent the Ax Men to

open

a Visto in the true Parallel

East of Monaungahela while

we are making our Observations.

Alpha Lyrae

1

10-

8

51+

1

45.8

1

8

14.2

6

49.5

Delta Cygni

4

50+

6

30-

1

24.7

4

51

24.7

4

49

Gamma Cygni

0

10+

6

8.5

1

35.2

0

11

35.2

8

0

Alpha Cygni

4

45-

10

43

0

26.0

4

44

34.0

11

17

Turned the Sector Plane WEST

313

Cloudy

Alpha Lyrae

1

10-

6

2.5

1

49.2

1

8

10.8

8

8-

Gamma Cygni

0

10+

4

48

1

31.5

0

11

31.5

3

8. 5

Alpha Cygni

4

45-

3

44

0

26.3

4

44

33.7

3

18-

Cape 11a

6

0+

14

38

0

49.5

6

0

49. 5

15

35.5

Alpha Lyrae

1

10-

7

6-

1

47.0

1

8

13.0

9

9-

Delta Cygni

4

50+

9

8.5

1

27.8

4

51

27. 8

10

44+

Gamma Cygni

0

10+

9

15.5

1

32.0

0

11

32.0

7

27.5

Alpha Cygni

4

45-

5

31-

6

26.0

4

44

34. 0

5

5-

Capella

6

0+

3

38-

0

49.8

6

0

49. 8

4

35. 5

Alpha Lyrae

1

10-

5

40-

1

49.6

1

8

10.4

7

45+

Delta Cygni

4

50+

7

35

1

27.0

4

51

27. 0

9

18

Gamma Cygni

0

10+

8

22.5

1

31. 0

0

11

31.0

6

35.5

Alpha Cygni

4

45-

6

15-

0

24.7

4

44

35. 3

5

42

Computing pur Observations as follows

Sent for the Ax Men from the East Side of the River Monaungahela.

188

1767

October

Plane EAST

Alpha Lyrae Delta Cygni

Olll O I II

12

1

8

14.5

12

4

51

23. 0

13

1

8

14.2

13

4

51

24.7

Mean

1

8

14.35

4

51

23.85

Aberration

+17.02

-18.39

Deviation

- 3.31

+ 1. 16

Precession

+ 9.53 ’

-31.40

Refraction

+ 1.20

+ 5.60

Mean Zen. Dist. Plane East

1

8

38. 79

4

50

40.82

Plane WEST

15

1

8

10.8

16

1

8

13.0

16

4

51

27. 8

17

10.4

17

27.0

Mean

1

8

11.40

4

51

27.40

Aberration

+ 16.84

-18.32

Deviation

- 3.31

+ 1. 16

Precession

+ 9.5d

-31. 50

Refraction

.+ 1.20

+ 5.60

Mean Zen. Dist. Plane West

1

8

35.69

4

50

44.34

Ditto Plane East

1

8

38.79

40.82

Mean Zen. Dist, 1 Jan. 1764

1

8

37. 24

4

50

42.58

Ditto at the Post Marked West

41.80

40.40

South 47 56 South 2V 18

2."18
OV 28

2V08 (Refer to page 316)

IV 15

ITI15 r 5 = 2V23 (mean) = 223 feet = 3 chains 38 links 315
to be laid off to the Northward.

Plane EAST
Gamma Cygni
o | n

Alpha Cygni
o i n

Capella

o i n

Mean

Aberration

Deviation

Precession

Refraction

Mean Zen. Dist. Plane East

Mean

Aberration

Deviation

Precession

Refraction

Mean Zen. Dist. Plane West
Ditto Plane East
Mean Zen. Dist. 1 Jan. 1764
Ditto at the Post Marked West

12

13

0 11 34.3

0 11 35.2

12

13

4

4

44 34.0

44 34.0

11

12

6

0 44.5

0 41.4

0 11 34.75

4

44 34.0

6

0 42.95

+17.30

-17.70

+ 5.49

- 0.00

- 0.61

- 5.61

+42. 00

-47.05

-19.98

+ 0.20

+ 5.50

+ 7.00

0 12 34.25

4

43 34.14

6

0 29.85

Plane WEST

15

0 11 31.5

15

4

44 33.7

15

6

0 49.5

16

0 11 32.0

16

4

44 34.0

16

6

0 49.8

17

31.0

17

35.3

0 11 31.50

4

44 34.33

6

0 49.65

+ 17.40

-17.80

+ 5.06

0.00

- 0.61

- 5.61

+42.10

-47.20

-20.04

+ 0.20

+ 5.50

+ 7.00

0 12 31.20

4

43 34.22

6

0 36.06

34.25

34. 14

29.85

0 12 32.72

4

43 34.18

6

0 32.95

33.00

31.20,

31.80

South 0”28

South 2l'98

South IV15

316

189

Hence the Offsets at every Mile Post to our last Station
at the Monaungahela as follows.

Miles from the

Offsets to

Offsets in

True Offsets

Post Marked West

the Circle

the Triangle

(North)

in Mr. Bryan's Field

B

c

Links

Chains

Links

Chains

Links

222.301

0

0

0

0

0

Here AbC the true Parallel. A the

223

7

0

22

0

15

Point begun at on the 29th of Sept.

224

15

0

53

0

38

B where the Sector was set up, on

225

21

0

84

0

63

the 11th of October where by the

226

25

1

15

0

90

Observations, BC = 3 chains 38 Links.

227

27

1

46

1

19

Hence the Offsets to the Chord ApC,

228

27

1

77

1

50

Column B, from which Subtract the

229

27

2

08

1

81

Offsets of the Chord to the Circle,

230

25

2

39

2

14

gives the true Offsets North (from

2$1

22

2

70

2

48

the Line run AB) as by Column C.

232

16

3

01

2

85

233

9

3

33

3

24

233.171

0

3

38

3

38

Note: The Sector stood on the top of a very lofty Ridge, but

when the Offset was made of 3 Chains 38 Links it fell a little

Eastward of the top of the Hills; we therefore extended the true

Parallel 3 Chains 80 Links Westward which fell on the top of the said

Ridge; there viz. at 233 Miles 17 Chains 48 Links from the Post marked West

in Mr. Bryan’s Field, we set up a Post marked W on the West Side and heaped

around it Earth and Stone three yards and a half diameter at the Bottom and Figure

five feet High. The figure nearly conical. 317

1767

October

19 The Ax Men Returned from the Monaungahela.

20 Began to open a Visto in the True Parallel
Eastward.

21 Continued the said Visto Eastward.

22 Continued Ditto*

23 Continued Ditto. This day we were joined by
the Hands we sent to open a Visto Eastward
on the 25th of August,

24 Continued the Line to the 225 Mile Post.

25 Sun. Received a Letter from the Honorable Thomas Penn, Esquire.

26 Continued the Line to the River Monongahela.

27 Continued the Line.

28 Continued Ditto.

29 Rain-

30 Continued Ditto.

31 Continued the Line to the 209th Mile Post.

Note: About 7 miles of the Weeks work was cut by the Hands sent
back on the 12th Instant.

November

1 Sunday

2 Rain,

3 Continued the Line.

4 Continued the Line. 31(

5 Continued the Line to the Post Standing at

199 Miles 63 Chains 68 Links which finished: There
being now one continued Visto opened in the true Parallel
from the Intersection of the North Line from the Tangent
Point with the Parallel to the Ridge we left off at on
the 9th of October last.

Mr. Hugh Crawford with the Indians and all
Hands (except 13 kept to Erect Marks in the
Line etc.) Left us in order to proceed Home.

6 Continued making marks in the Line as before.

7 Continued Ditto to the 195th Mile Post.

190

1767

November

8 Sunday

9 Continued Making Marks,

10 Continued Ditto.

11 Continued Ditto.

12 Continued Ditto. Snow.

13 Continued Ditto. Snow about 2 Inches deep.

14 Continued Ditto the 177th Mile Post.

15 Sunday

16 Continued Ditto.

17 Continued Ditto.

18 Continued Ditto. Snow and moved to the foot of Savage
Mountain on the West Side.

19 Continued Ditto. Snow 12 or 14 Inches deep. Made a pile
of Stones on the Top of Savage or the great dividing
Ridge of the Allegany Mountains.

At 169 miles 26 chains being in the West side of Savage Mountain
a small Run which is said to run Northward and then through
a gap in Savage Mountain in to Wills Creek.

20 The weather being so bad our Hands would not

proceed on their work. We then proceeded to Mr. Kellams (in

the Road from Fort Pit to Fort Cumberland) at the Gap in Savage Mountain.

21 Seven of our hands left us.

22 Sun. Proceeded to Mr. Tumblestone’s in Wills Creek Valley.

Employed more hands.

23 Set a Pile of Earth etc. on the Top of Little Allegany Mountain.

24 Set a Pile on the Top of Wills Creek and the Nobbley Mountain.

25 Set a Pile on the Tops of Eivits and Flintstone Mountains.

26 Set Ditto on the Tops of the Big Warrior and Little Warrior Mountains.

27 Set Ditto on the Ragged Mountain.

28 Set a Pile at 143 miles 14 chains. Proceeded to

the Top of Town Hill.

Where we found hands at work which had just finished
a Pile employed by R. Far low whom we dispatched on
the second of October to set stones in the Lines, Piles, etc.

29 Sun. At Town Hill, Discharged Six Hands.

30 Piles being set by R. Farlow at 137 miles 11 chains and the
Top of Sidelong Hill; and the Stones at the proper
places* to the 135th Mile Post from the Post marked West
which reached to Sidelong Hill (inclusive) we proceeded

to Mr. Matson’s in the Conollaways.

Sent Mr. Jonathan Cope (chain carrier) along the
Line over the North Mountain to see that the Stones are
at their Proper Places.

*excepting the 80th Mile Post which is 125 Yards East
of its true Place: The true place of the Mile Post falling
in Marsh Creek was the reason of its being placed East.

The 120th Mile Stone stands five yards East

of its true Place; it could not be set at its proper place

for a great Stone.

The above Mentioned Mile Posts, viz. 135th, the 80th and 120th
are the 132nd, the 77th and the 117th from the Beginning
of the West Line.

December

4 In Coneeocheague.

Sent Expresses to Annapolis and Philadelphia to acquaint
the Gentlemen Commissioners we shall be in Philadelphia the
15th Instant.

10 At Brandywine. .

11 Received a Letter from Benjamin Chew, Esquire (one of the Gentlemen Commissioners)
acquainting us that the Commissioners were to meet at

Christiana Bridge the 23rd Instant.

319

320

321

mi

Gentlemen:

I received your favor of the 4th Instant and
have only to inform you that we wrote yesterday to the
Maryland Commissioners to meet us at Christiana Bridge
on Wednesday the 23rd Day of this Instant. We expect
them to confirm and put an end to this tedious Business
so as to leave nothing more to be done than setting
up the remainder of the Boundary Stones if it is
possible to get them to their proper Stations at an
Expense which can be borne. Wherever you may be in
the Mean Time we hope to have your Company at
the Bridge on the 23rd. I am Gentlemen,

Your Humble Servant

Philadelphia, Dec. 10, 1767 Benjamin Chew

Editorial Note:

Here we have an envelope addressed to
Messrs. Mason and Dixon)

1767

November

19 Our Journal from the 19th of November I have described for the Commissioners
as follows (See original document—inconclusive.)

Continued the Erecting Marks in the Line.

Snow 12 or 14 Inches deep. Made a Pile of Stones on the Top of
Savage or the great dividing Ridge of the Allegany Mountain.

Note: West of this Mountain to the End of the Line the Mile Posts
are 5 feet in length, 12 Inches Square, and set 2 feet in the Ground
and round them are heaped Earth or Stone 8 feet in Diameter at
Bottom and 2. 5 feet High.

20 The Weather being so bad our Hands would not proceed
on their work.

21* Seven of our Hands left us.

22 Sun. ** The above Desertion of our Hands prevents us from

making Heaps around the Mile Posts as before.

Proceeded in to Wills Creek Valley.

23 Continued Erecting Marks on the Tops of the Mountains,

Got more Hands,

24 Continued Ditto,

25 Continued Ditto,

26 Continued Ditto,

27 Continued Ditto.

28 Continued Ditto. Marks are now set on the Tops of all the High

Ridges and Mountains to the Top of Sidelong Hill.

29 Sun. Discharged most of our Hands.

Note: The Mile Posts between the Top of Savage Mountain and the
End of the Line have Heaps of Earth or Stone Round them
(as observed in Minutes of 19th November) of Eight feet Diameter at

Bottom and 2 1/2 feet High. 324

(Editorial Note:

*This date appears erroneously listed by Mason as 27th Nov.

**This date also appears to be in error and is corrected herein.)

192

(Undated) At the following Points in the Line, being the Tops of

High Ridges and Mountains, are set Posts about 12 Inches Square
Marked W on the West Side, and around them Heaps of Earth
or Piles of Stone Three Yards and a half Diameter at Bottom
and five feet High: none less, but many four Yards Diameter and
Six or Seven feet High.

Miles from the Post Marked

West in Mr.

Bryan's Field.

Miles

Chains

135

29

The Top of Sidelong Hill

137

11

140

54

The Top of Town Hill

143

14

146

52

The Top of the Ragged Mountain

149

17

Little Warrior Mountain

151

47

The Great Ditto.

153

22

Flintstone Mountain

155

■:T 32

Evit's Mountain

157

63

Nobbley Mountain

159

71

Will's Creek Mountain

163

59

The little Allegany Mountain

168

76

The top of the Allegany Mountain

172

27

173

75

176

46

Top of little Meadow Mountain

178

53

182

19

184

17

Top of little Laurel Hill

185

45

186

63

187

50

190

12

The Top of Winding Hill

193

25

196

20

198

63

199

63

202

44

205

16

207

45

209

19

210

60 1

On Laurel Hill

212

26 )

214

12

The Top of the Highest Ridge on Ditto

217

58

218

67

220

51

222

24

223

14

226

40

227

57

228

64

229

75

230

77

233

17

The top of the Westernmost Ridge to which the Line is Extended.

Some of these Mountains not being at Right Angles to the Line 1st Run; Causes these Points to
be something different in distance from the Post marked West, from what is laid down before
the Line was corrected by Offsets.

From the Points 168 Miles 76 Chains There is an Extensive View Eastward and Westward.

214 Miles 12 Chains The Line may be seen to Winding Hill,

And, to the End, Westward; from these Points the Curvature of the Line appears very regular.
The Stones are extended from (the 65th Mile) where they Ended last Year, to 132 Miles
from the Beginning of the West Line; They are all set in the same manner as described
in Minutes of the 20th of November 1766; and are all at their Proper places except the
77th and the 117th. The Place of the 77th falling in Marsh Creek, it is Set 125 Yards East
of its true Place. The Place of the 117th falling on a Great Stone it is Set five yards East.
The 64th Mile which was left last year, is also Set.

193

This day received of Mr. Peters
the following Letter from Mr.
Penn. N. B. The seal was
broke.

1767

December

4

24

25

26

28

1768

January

6

8

13

19

In Cone coc he ague.

Sent Expresses to Annapolis and Philadelphia to acquaint
the Gentlemen Commissioners that we shall be iri Philadelphia
the 15th Instant.

Thus far the same as to the Commissioners from the 19th of November.
Attended the Gentlemen Commissioners at Christiana Bridge.

Attended Ditto.

Attended Ditto: When the Gentlemen Commissioners read their
Minutes to us, by which we understand they have no further
occasion for us to run any more Lines for the Honorable Proprietors,
(but they did not choose to give us a discharge in writing).

Received Instructions to Draw a Map or Plan of the Lines,
and to give it in to either the Commissioners for Pennsylvania
or Maryland; as soon as possible.

The Gentlemen Commissioners also asked us for the Length of
a Degree of Longitude in the Parallel of the West Line.

At Brandywine.

Left Ditto and went to Philadelphia.

Gave into the Hands of the Reverend Mr. Peters (one of the

Gentlemen Commissioners) the following: Directed to the Gentlemen Commissioners
for Dividing the Provinces of Maryland and Pennsylvania.

By comparing our mensuration of a Degree of the Meridian
with that made under the Arctic Circle, supposing the Earth
to be a Spheroid of a uniform Density: a Degree of
Longitude in the Parallel of the West Line is 53. 5549 Miles.

But the Earth is not known to be exactly a Spheroid,
nor whether it is everywhere of equal Density; and our
own experiment being not yet finished: We do not give
in this as accurate.

At Brandywine.

Measured the Rods sent in by the Royal Society, and found
them too Long for the Standard (brass rod of 5 feet).

Thermometer at Freezing.

Duplicate

Messrs. Mason and Dixon

I have received your Letter of the 6th of January with a particular account
of your proceedings since your last, and we are very well satisfied with the
accounts you give of them. We apprehend that you cannot have put Stones
at every mile of the Line, from Cape Henlopen to the middle of
the Peninsula, or in the Tangent Line, unless you had many made in
Pennsilvania; the particular places you have noted down (where the
Parallel of Latitude has crossed) we are very well pleased with; as
we are, that you made use of your time, when not employed by us,
to run the Degree of Latitude for the Royal Society, about which my Lord
Morton often speaks to me.

I am at a loss to know, what was the Commissioners’ reason
for ordering you to run the parallel of Latitude from the place where
the Meridian Line intersects it, to the River, as I have not received from
them their minutes, and when you write next let me know them, lest
they should omit it.

I shall expect to hear further from you, if you proceed to extend
the Line farther Westward, in the mean time remain

London, June 17, 1767

Your affectionate Friend
Thomas Penn

326

327

328

194

Messrs. Mason and Dixon

I was very well pleased to find by your Letter of the
12th of June, that you had received an account that the Indians had given their
consent to Sir William Johnson that you might extend the division Line between
Maryland and Pennsilvania to the extent of the province of Maryland, and that
you were to receive your Instructions from the Commissioners the 16th of the same
month. We sent several months (since) one hundred and forty Stones, and am
now shipping to Maryland sixty eight, which we think will about compleat
the work, which we hope to hear you will finish this Year. I am

Your very affectionate Friend

London August 7, 1767
(Undated. 'An envelope addressed as follows)
To

Messrs. Mason and Dixon
in

Philadelphia
By Mr. Hamilton

Thomas Penn

330

1768

January

19

Sun Eclipsed

27

28

29

lOh

19m

22

26

29

Watch

Sun's Limbs
by Reflection

Time

by the

Watch

40s

49°

03*

lh

53m

45s

20

49

26

1

51

00

5

50

4

1

47

30

20

50

36

1

44

30

35

00

52

43

37

00

52

58*

39

40

53

21*

53

00

55

18*

55

40

55

38*

59

00

54

51*

llh 2

35

55

16*

8

10

55

51*

17

30

56

45*

To these numbers add 2*

30”

for adjustment of the Quadrant: Th<

Equal Altitudes of the Sun's Lower Limb
In the afternoon Observations the Sun's
Lower Limb was rendered dubious
something, by the Moon's Body.

Altitudes of the Sun's Upper Limb

Ditto for the Sun's Lower Limb

the Half is the approximate Altitudes of the Solar Limbs; as they were
all made by reflection with a Hadley's Quadrant.

The air was very Hazy during all these Observations, except
those marked * at which times the solar Limbs appeared clear.

At the Beginning of the Eclipse the Air was so thick
the time could not be determined to any certainty: At the
End the Sun was entirely hid by clouds.

At the Middle the Sun (through a Haze) appeared to be about 10 Digits
Eclipsed. At this time the usual light was
very much diminished.

Left Brandywine and went to Philadelphia.

Wrote to the Astronomer Royal, and M: Katy, Esq., S. R. S.

To Mr. Williams, Mr. Kingston and Mr. Carrier the 30th day.
Delivered to the Rev. Richard Peters, Plans
of the Lines Dividing the Provinces of Maryland
and Pennsylvania.

Wrote to the Honorable Proprietors of Ditto, acquainting
them of our proceedings since the 12th of June last; and that
we had no further Instructions to execute from the Gentlemen
Commissioners; but were preparing to remeasure the Line
for the Royal Society. Wrote to Mr. Bird.

331

195

1768

January

31 Sun. Examined the Sector and Transit Instruments at the State House
and found them good.

February

1 At Brandywine,

2 At Mr. Joel Bailey's who is making two levels in

order to carry two of the Rods each, as by the figure following.

The Rods having been a long time kept in a Dry room
I measured them when the Thermometer stood at 54?5

(the brass standard of 5 foot having been kept by the Thermometer), and found
them all = the standard except that marked B, which was at least three
of the divisions at the End of the brass standard, too long.

I ordered the Rods to be kept in the Open Air and Wet.

4

Thermometer at Sun rise
Thermometer at Sun rise

25°.

27°.

At 2h P. M.
At 3h P. M.

38°. )
38°. >

Placed in the Open
Air on the North Side

Thermometer at Sun rise

32°.

At 3h P.M.

36°. )

of a House.

The Rods having been kept wet (in snow since the 4th at Night)
and in the Open Air since the second; and the Standard Brass in
a room; in to which I brought the Rods and Thermometer;

The Thermometer rose to 54°. I then measured the Rods.

! A four Divisions \

B six Ditto / too long: This was done at 3h P. M.

C four Ditto f

D four Ditto )

I kept the Thermometer and brass standard together 'till 8h P.M.

and the room in the same state of heat (viz. Thermometer 53°, 54° and 55°)

and measured the Rods, and found them the same as before.

6 I laid the Rods* to the Levels, which were adjusted

to the Rods when the Thermometer stood at 55° and the rods had been dry a long time; and
found the Rods were too long for the Levels by the Quantity above.

The Levels had always been kept in the dry. I now '
put the Levels with the Rods out in*the Open Air.

Corrected the Rod B and made it = A = C = D.

Hung up Plumb Lines of silver wire at the Middle and Ends of the
Levels and found they corresponded extremely near.

* The Rods having been put out all night in the Wet and open Air, and the Levels still in the Rain.

332

10 Examined the Levels and found they were now too long for the

Rods. The weather has been very moderate since the 6th, never
colder than just freezing.

18 Mr. Bailey informed me the Levels still continued too long for the Rods,

as on the 10th Instant. The weather very moderate
(some snow) since the 10th Instant: not colder than just freezing.

Mr. Bailey brought to Mr. Harland's the Levels: (each 20 feet in Length)
for measuring the Lines.

Began at Ditto in the Parallel where the Sector was set up in 1764
and in December 1767 to remeasure the Line with the Levels for
the Royal Society; the Levels having the Rods (sent us by the Royal Society)
first to them: The Measuring the Lines with the Rods by laying them End
to End being impracticable.

From the Point where the Sector stood to a mark on
o

g the North Side of the River Brandywine = 17 Levels.

. (At lOh A. M. measured with the Brass Standard one Rod and found it
Sj <3 Divisions too long: Therefore the 4 Rods = 12 Divisions
£ (too long by supposing all the Rods equal.

AB the Creek or River. — measured by the Cord, 8 Levels wanting 8 Inches.

At 3h P.M. The Rods as before. Thermometer 53°.

From B, the South Side of the Creek, to the next mark on the North Side
of Ditto = 6 Cords and 8 Levels = 86 Levels.

Here also AB the Creek.

From B on the South Side a second time to a

mark on the North Side a third time = 7 Cords Figures a and b

and 9 Levels = 100 Levels. 333

1 %

1768

February

24

Here AB the Brandywine a third time (A the South Side)

Altitude of A above B about 20 feet
by estimation; or 8° Elevation by the Quadrant:

At 9h A. M. Thermometer 54° one of the Rods two divisions longer than the Brass.

Therefore suppose the 4 Rods = 3 Divisions Longer

At lh 30m P. M. Thermometer = 44°, one Rod 3 Divisions too long.

Measured in all this day 25 Cords besides the Creek. 13 Levels = one Cord
as before.

At 5h P.M. Thermometer 39°. One Rod 8 Divisions too long.

This day we measured different Rods and found they are not

of equal lengths. Though they were all equal to the Standard when the Thermometer
stood at 55° (excepting B which was corrected on the 6th Instant) see Minutes of the
second Instant.

26

At 9h 30m A. M.

Rods

ji:!}

Divisions Longer J

N. B.

Thermometer 40°

) c = 2(

than the Brass >

(d= 2 ;

Standard J

16 Cords and one Level wanting 3 feet 8 Inches reached the
Stake on the South Side of the Road leading from
At 4h 30m P.M. f A. = 3.5)

Thermometer 45° IB = 2 (Divisions Longer

jC = 2 fthan the Brass Standard

(d = 3 . 5 ;

Each of these Divisions
is - 1/100 part of an Inch.

Measured in all this day 19 Cords:
each Cord =13 Levels as before*

27

28 Sun.

29

March

1

2

Rain.

At Mr. Jacob Dwight's.

At 8h 30m A. M. fA = 4 )

Thermometer 60° )b = 0 ( Longer than
1C = 0 l the Standard
ID = 4 )

Measured in all this day 8 Cords: Each
Cord now = 10 Levels.

Rain in the Afternoon and Snow at Night.

Divisions

( A = 8 )

At 9h 00m A. M. ) B = 3 ( Longer
Thermometer 32° )C = 5 t
v D = 7 /

SinceQh A. M. measured 25 Cords
and after 4h 30m P. M. Ditto 7 Cords,
Measured in all this day 32 Cords,
each Cord =10 Levels as yesterday.
At 8h 30m A. M.

Thermometer 32°

At lh 00m P. M.
Thermometer 41°

Longer

Longer

At 4h 30m P.M.
Thermometer 42°

Divisions
A = 6
B = 4
C = 5
D = 6

Longer

Measured 20 Cords

(A =5 j

At 5h 30m P. M. 1B = 0. 5 (Longer
Thermometer 48° JC - 2 (

(d = 4 >

Measured 17 Cords.

In all this day 37 Cords: Each
10 Levels as before

Figure

334

335

197

1768

March

3

At 8h 15m A. M, (A = 7. 5 \

Thermometer 40° \ B = 2 f Longer than
JC = 3 l the Standard
vD = 6 ;

Measured 13 Cords and 7 Levels which reached
to the Mark on the North Side of the Road
leading from Philadelphia to Nottingham.

A = 5 )

(]

At 2h P.M.
Thermometer 48°

Measured 23 Cords.

At 5h P.M.
Thermometer 48°

Longer

Longer

Since 2hP.M. measured 12 Cords.
In all this day 35 Cords: Each
10 Levels as before.

At 8h 30m A. M. fA
Thermometer 31° 1 b
c
ID

Measured 20 Cords,

(A

At 2h P.M.

Thermometer 38°

6 . 5 \

3. 5 (Longer than

4. 5 (the Standard
4.5;

JB -

JC-

\D =

In all this day 35 Cords.

( A =

At 8h A. M. 1B =

Thermometer 27° jC =

(Longer

At 5h 30m P
Thermometer

( A

.M.

ir 30°)C
\D

5.5

2.5
3

5 ;

Each 10 Levels as before,

7 )

3 { Longer At lh P.M.

4 l Thermometer 41°

4;

A = 5.5'
= 2. 5 1
= 4. 5
= 6 -

! A = 4.

B ~ 1

C = 2.
D = 4

Longer

Measured 15 Cords since
2h P.M.

Five Cords three Levels and 17 feet reached
the Mark near Mr. Milhous e's.

(A = 5. 5 j

(i

Longer

Since 8h A. M.
22 Cords

we measured

At 5h 30m P. M.
Thermometer 29°

[Longer

6 Sun.

7

) B = 3
c = 4
Id = 4 ;

Since lh P.M. measured 12 Cords.
At Mr. Allen's.

In all this day 34 Cords, Each Cord - 10 Levels as before.

336

At 8h 15m A. M.
Thermometer 28°

5/J

Longer than
2,5 (the Standard
3. 5 J

Very dry winds with Frost.

At 2h P.M.

Thermometer 38°

Longer, We have now
measured 25 Cords,

Measured all day 30 Cords wanting 3 Levels 12 feet.
/ A - 4

A marked Stump.

At 5h 45m P.M,
Thermometer 36°

B -
C =

l D =

In all this day 34 Cords:

( A =

At 8b A.M. ) B =

Thermometer 36° J C -
* D ^

Longer

Measured 9 Cords since 2h P,
Each Cord as before,

5
2-
1

2.5)

M,

Longer than
(the Standard

198

1768

March

8

At lh 30m P* M*
Thermometer 52°

At 5h 30m P. M,
Thermometer 45°

In all this day 40 Cords.

At 8h 15m A. M.
Thermometer 51°

Longer

Shorter than the
Standard, Since 8 A, M.

Longer

1*5/Measured since 5h 3 0m 17 Cords.
Each Cord 10 Levels as before.

5;:

Longer

measured 23 Cords,

At 2h 00m P. M.
Thermometer 66°

B = 3.5 (Shorter than the
I C = 3.5 f Standard

, D = 2. 5/Since 8h A, M. measured 27 Cords,

10

12

At 5h 30m P. M.
Thermometer 52°

Longer

In all this day 38 Cords:

At 8h 45m A. M.
Thermometer 58°

0. 5/ Shorter

0 ) Since 2h 00m P.M. measured 11 Cords

Each 10 Levels.

2 Longer

1.5 | . i

1. 5 /Shorter than !

0 /the Standard

Measured 15 Cords 3 Levels 3 Feet which reached the
Point where the Sector stood in Mr. Bryan's field.

And 18 Cords wanting 16 feet or 17 Cords
nine Levels and four feet reached to the Post
marked West in Mr. Bryan's Field.

That is Measured in all this day 17 Cords 9 Levels 4 feet which
we finished at Oh 30m P. M.

Longer

Thermometer then

at 61° )C = 2 >Shorter than

)the Standard

Began at the Corner in the West Line

At llh A.M.
Thermometer 600

{ A = 1.5

!!•'}:

x in the \

(S:j)

The Rods Shorter
than the Standard

Measured Five Levels and 3 feet from the Corner to the Mile

Post. Began again at the Mile Post and

Measured 11 Cords. Each Cord - 12 Levels

which we propose using all the way: 22 of

the said Cords = a Mile,

Rain in the afternoon.

Measured in all this day 11 Cords 5 Levels 3 feet.

At 9h A. M.
Thermometer 52°

The Rods Longer
than the Standard

Measured 9 Cord*
At 3 P.M.
Thermometer 58°

linger 1
Shorter

f A= ]

) E = D + 5

\c - 0

l D = 0.5 Longer f

When we had measured a Mills by the Levels it
wanted E, 5 feet o: the 1st Mile StOnd.

Than the
Standard

Figure

337

338

199

1768

March

12 l A = 3 I

At 5h 30m P. M. JB = 2-( Longer
Thermometer 53° yC = 1 )

f D = 2+1 Measured 13 Cords since lh P. M.
Measured in all this day 22 Cords = 1 Mile.

The Cords being each = 12 Levels as yesterday

13 Sun. At Newark.

14 Preparing Plumb Staff, etc., for to measure with

15 one Level only by an internal Contact.

15 Attempted to measure with one Level, and found

it impracticable.

17 Began where we left off on the 12th Instant to measure as

before.

! A = 3. 5 i

B = 1 ( Longer than

C = 1. 5 (the Standard
D = 3 1

A - 3.5 1
B = 2. 5 f Longer
C = 0.5(

D = 2.5 1

Since lOh A.M. measured 11 Cords
When we had measured 2 miles; it wanted
14 feet of the second Mile Stone.

\A = 3J

At 5h P. M. < B = 2 V Longer

Thermometer 36° yC = 1?

f D = 2 ]

Measured since 2h P. M. 12 Cords

In all this day 23 Cords, each Cord = 12 Levels as before
18 lA = 3.5y

At 8h 30m A. M. lB = 0. 5f Longer than
Thermometer 36° yC = 1 rthe Standard

Id = 3.51

When we had measured by the Levels three Miles; it
wanted one Level 2 1/2 feet of the 3rd Mile Stone.

lA-Sj

Longer

At 2h P. M.

) B = l(

Shorter than the Standard

Thermometer 42°

fe:i

Longer

We have measured since 8h 15m A. M. 22 Cords = 1 Mile
l A = 2 <

At 5h 30m P. M. )B = 1 f Longer than
Thermometer 35° yC = 2 +t the Standard
fD= 2 )

Measured since 2h P.M. 13 Cords.

In all this day 35 Cords; each 12 Levels as before.

N, B. That at 33 Cords the 4th Mile Stone was opposite :: as near as could be Judged. The

stone being on the Circle * at a Distance from the Meridian

The 1st Mile Post from the Tangent Point as last measured;

was five Levels South of our 4th Mile made by the Levels, that is when we had

measured by the Levels 4 Miles it wanted 5 Levels of the 4th Mile Stone or Post,

The Chain Carriers made a Mistake in Measuring the 1st time from the Tangent

Point to the West Line; see Journal minutes of the_.

^Circle Round Newcastle of 12 Miles Radius.

At 2h P.M.
Thermometer 40°

339

200

1768

March

19

20 Sun,

21
22

23

24

27 Sun.

28
29

At 9h A. M.
Temperature 36°

A = 4
B - L 5

iC * 2

D = 4

Longer than
the Standard

, Longer than Ditto

\ A = 5 /

At Noon J B = 2 V, Longer than Ditto

Temperature 31° JC - 4 £

*D = 3.5)

Measured in all this day 19 Cords five Levels and 7 feet which
reached the Tangent Point.

1st day measured

11 Cords

5 Levels

3 feet

2nd Ditto

22

0

0

3rd Ditto

23

0

0

4th Ditto

35

0

0

5th Ditto

19

5

7

110

10

io = 5:

= 5 Miles 3 chains 18 Links

Sent to Philadelphia for Tents, Blankets, etc.

Examined the Levels by Plumblines hung at the Ends of the Levels; and
found them all good except one which we had altered a little on the 16th
Instead of endeavoring to measure with one Level.

Having found it very troublesome to keep the Levels equal in Length
to the Rods, we fixed pieces of Brass on the Levels at every 5 feet, and
drew a Division on them: and began to measure the Levels themselves
instead of the Rods.

Began at the point where the 12 Mile Line from Newcastle crosses our
1st Line.

The Level marked B = 8 Divisions at the End of the Standard shorter than the Standard.
Ditto D = 0 Thermometer 49°

Measured in all this day 11 Cords. Each Cord * 12 Levels; which length
will always be used.

At Newark.

Corrected the Level B and made it = the Standard: that is 4 times
the standard Brass Rod = one Level.

At Noon the Level D 5 Divisions Shorter than 4 times the Standard.

Thermometer 5 7°

Measured 10 Cords 7 Levels 1 foot which reached the 81 Mile Post.

Began again at the Mile Post and Measured 7 Cords.

At 6h P. M. the Level fB 8 Longer \ c , . ,

Thermometer 43° t D 1 1 / 2 Shorter / than the Standard

Measured in all this day 17 Cords 7 Levels 1 foot
At Mr. Williams's.

Snow.

At 8h A.M. the Level fB 14 Divisions) Longer
Thermometer 40° ID 5 Divisions)

Compared two Thermometers and they agreed within one Division.

At the 80th Mile Pogt we were behind the Mile Post 14 feet and 8 Inches.

At 2h P.M. fB = 11 Longer

Thermometer 47° I'D = 2 Shorter Measured since 8 A.M. 22 Cords

Thermometer 47 l

At 5h 30m P. M. f

Thermometer 40° \

In all this day 44 Cords
At 8 1/2 A.M. 1

Thermometer 38° 1

= 2 Shorter

=9.5 Longer
= 1.5
2 Miles.

= 11) Long
= 3)

fB = 9.5 I
ID = 1.5
s = 2 Miles

When we came to the 78th Mile; we were 2 Levels 5 feet
behind or short of the Post.

At 2h 30m P. M. fB = 5 ^Longer

Thermometer 61° ID = 2. 5/Shorter

Measured 24 Cords since 8h 30m A. M.

At 6h 15m P. M. fB = 11 Longer

Thermometer 45° (D = 1 Shorter

Measured since 2h 30m P.M. 16 Cords.

In all this day 40 Cords.

Since 2:00 P.M. measured 22 Cords

340

341

201

1768

March

31

April

1

2

3 Sun.

4

5

6

At 8h 15m fB = 12) Longer

Thermometer 45° ID = 3 /

At 2h P. M. IB- 9.51 Long

Thermometer 62. 5°(D = 1 j

Measured 17 Cords.

When we came to the 76th Mile, we were three Levels
and a half behind the 1st Mile Post.

At 6h 30m P. M. (B = 12) Longer
Thermometer 49° ID = 5 J
Since 2 P. M. measured 16 Cords.

Measured in all this day 33 Cords.

Broke one of the Thermometers.

js = 13 i

(D = 6.5)

Longer

At 8h A. M.

Thermometer 39°

At the 75th Mile we were 4 Levels 4 Feet
behind or short of the Mile Post.

At 2h P.M.

Thermometer 52°

Since 8h A. M. measured 27 Cords,

{HI!

Longer

fB = 12. 51
ID = 6.5J

Longer

At 6h P.M.

Thermometer 35°

Measured since 2h P.M. 17 Cords.
Measured in all this day 44 Cords.

= 13
= 5

K

I

Long

Long

At 9h A.M.

Thermometer 40°

At 2h 30m P.M.

Thermometer 46°

Measured 19 Cords.

At the 7th Mile we were 6 Levels 7 Feet
behind the Mile Post.

At 6h 15m P.M. fB=111 Longer
Thermometer 37° lD= 4 j
Measured since 2h 30m P.M. 14 Cords.
Measured in all this day 33 Cords.

At Mr. Turner's at Bead of Bohemia.

At 9h 30m A, m.

/B =

5 1

Longer

Thermometer 38°

ID =

1 )

Shorter

At 3h P. M.

| B =

10)

Longer

Thermometer 51°

ID =

2 /

Since 9h 30m A. M. measured 26 cords: and
after this when we had measured 15 Cords and
8 Levels wanting 9 Inches it reached the 70th
Mile Post.

At 6h P. M. fB = 10 1 Longer

Thermometer = 36° l D = 3 /

Measured since 3h P.M. 16 Cords.

Measured in all this day 42 Cords.

Snow in the Evening.

Snow.

At 8h 30m A. M. f B = 10 1 Longer

Thermometer 37° ID = 4]

Measured 16 Cords to the Mark on the North Side of Bohemia River.
In Figure 1 AB =
the Line crossing the
River Bohemia obliquely.

AC or Base on the
North side of the River.

The Angle C found from
Figure 2 -

The Angle C in Fig. 2 = the Angle C in Fig. 1.

342

343

202

1768

April

6

7

8

Measured from a Mark at B on the South side of the
River to the North side of a Fork of the River = 3 Cords
At 3h P.M. iB = 10/ Longer

Thermometer 51° «D = 3f

At 6h 15m P.M. iB = 10. 5i Long.

Thermometer 38° = 2.5*

Since 3h P.M. measured 17 Cords. One of these was measured with
a Cord over the Fork of the River mentioned above.

Measured in all this day 36 Cords; besides theRiver Bohemia.

Snow all day and frost at Night.

‘AtllhA.M. jB=16i Long.

Thermometer 37° 'D = 7 »

Measured 27 Cords and 7 feet which reached

the 67th Mile Post.

At 6h 15m P. M. iB = 10. 5i Longer

Thermometer 40° ' D = 5 >

Measured in all this day 33 Cords.

9 At9hA.M. iB s 12 i Longer

Thermometer 44° *D= 4. 5 \

Measured the Brass Standard by a foot Sector made
of Ivory by Mr. Bennet and found it wanted 0. 15 of an
Inch in 5 feet. Thermometer as above.

Measured 16 Cords one Level and 3 feet which
reached the 66th Mile Post.

At 2h P. M. i B = 5 Longer

Thermometer 57° 'D = 5 Shorter

Tried the Standard again by the Sector and found
it the same as above.

Since 2h P.M. measured 17 Cords.

At 6h P.M. iB = 5 Longer

Thermometer 51° 'D = 3 Shorter

Measured in all this day 33 Cords.

10 Sun. At Warwick.

11 At 9h A. M. iB = 3+ Longer

Thermometer 59° 'D = 5 Shorter

At 5 Cords 1 Level 18 feet - the 65th Mile Post
At 2h 30m P.M. iB = 5) Shorter

Thermometer 66° <D = 11'

Measured since 9h A. M. 24 Cords: and

then measured 3 Cords 2 Levels 14 feet which reached the 64th
Mile Post.

At 6h 30m P.M. iB = 2 1 Shorter

Thermometer 59° 'D = 8*

Measured since 2h 30m P.M. 19 Cords.

Measured in all this day 43 Cords.

12 At 8h A. M. iB = 2.5 Longer) Mr. Dixon has

Thermometer 47° 'D = 4.5 Shorter*

At 6 Cords 3 Levels 11 Feet the 63rd Mile Post.

At 3h P.M. iB = 3 i Shorter

Thermometer 70° «D = 11 »

Measured since 8h A. M. 29 Cords.

At 6h P.M. iB = 3 Longer

Thermometer 60° <D = 6 Shorter

Measured since 3h P.M. 13 Cords.

Measured in all this day 42 Cords.

jB = 2.5

<D = 4. 5

Figures a and b
344

Shorter

Longer

345

203

1768

April

13

At 9h A. M. <B = 0

Thermometer 64° /D = 8 Shorter

At 8 Cords 5 Levels 4. 5 feet the 61 Mile Post.

At lh P.M. (B = 1. 51 Shorter

Thermometer 76° |d = 9 f

Since 9h A. M. measured 20 Cords.

At 30 Cords 6 Levels 1 foot the 60th Mile Post.

Since lh P. M. measured 13 Cords.

At 6h P. M. | B = 0 j Shorter

Thermometer 64° / D = 7)

Measured in all this day 33 Cords.

At 8h 45m A. M. f B = 3 Longer

Thermometer 53° | D = 5 Shorter

At 19 Cords 6 Levels 16. 5 feet the 59th Mile Post.

Since 8h A. M. measured 33 Cords.

At 4h 30m P. M. |b = 4 Longer

Thermometer 53° j D = 4 Shorter

Measured in all this day 33 Cords.

15 At9hA.M. j B = 12/ Longer

Thermometer 45° j D = 6)

At 8 Cords 7 Levels 13 feet the 58th Mile Post.

Measured in all this day 22 Cords.

Note: This reached all most the South side of Esquire Delany's Fields.

Did not measure the Levels again it raining very fast. This day

we passed through swamps two feet deep in water nearly half the way. 346

16 At 8h A. M. <3=15/ Longer

Thermometer 46° /D - 5)

At 8 Cords 8 Levels 7. 5 feet the 57th Mile Post.

At 30 Cords 9 Levels 2. 5 feet the 56th Ditto.

Measured since 8h A. M. 33 Cords.

At 4h P.M. (B = 13 / Longer

Thermometer 560 |d = 7. 5 j

Measured in all this day 33 Cords.

17 Sun. At Mr. Bucks.

18 At 8h 15m A. M. jB = 2. 5/ Longer

Thermometer 52° |D = 9 )

At 19 Cords 9 Levels 15. 5 feet, the 55th Mile Post.

At Noon (B = 2 Longer j Since 8h 15m measured

Thermometer 67° |d = 4 Shorter J 22 Cords.

At 6h 30m P. M. = 2 Longer

Thermometer 58° (D = 3 Shorter. Since Noon measured 16 Cords.

Measured in all this day 38 Cords.

Found one joint when the Levels were exactly
Plumbed did not quite correspond: Corrected it.

19 At 8h 30m A. M. \b = 1 Longer

Thermometer 53° (D * 0

At 3 Cords 10 Levels 8 Feet, the 54th Mile Post.

At 25 Cords 10 Levels 18. 5 Feet, the 53rd Mile Post.

(Measured since 8h 30m A. M. 37 Cords.

} At 3h P.M. B = 1 / Shorter

lThermometer 74° D = 6.5)

At 47 Cords 11 Levels 11 feet the 52nd Mile Post.

After 3h P.M. measured 11 Cords.

Measured in all this day 48 Cords. 347

20 At 8h 30m A. M. j B = 5 Longer

Thermometer 570 /D = 2.5 Shorter

At 22 Cords and two feet the 51 Mile Post.

Since 8h 30m A. M. measured 26 Cords.

B= 1.5/ shorter

D= 5 j

B = 4 [ Longer

D = 6 j Shorter Since 2h 30m P.M. measured 18 Cords,

At 44 Cords and 15 feet the 50th Mile Post.

Measured in all this day 44 Cords.

At 2h 30m P.M.
Thermometer 78°
At 6h 30m P. M.
Thermometer 61°

204

1768

April

91

At 8h 30m A. M.

} b =

7

Longer

Thermometer 52°

ID =

1

Shorter

At lh 30m P.M.

J B =

5

Longer

Thermometer 75°

«D =

3

Shorter Since 8h 30m A.M. measured 22 Cords.

At 22 Cords 1 Level 6 feet the 49th Mile Post.

Measured 11 Cords after lh 30m P. M.; and left off in a Swamp of Water 18 Inches deep.

Measured in all this day 33 Cords.

22 ) At Mr. Bostock's. Rain day and night.

23 l

24 Sun. Rain until llh A. M.

25 ) Swamps so full of Water we couldn't proceed.

26 J

27 At lOh A. M. tB * 3 Longer

Thermometer 73° *D = 3 Shorter

At 11 Cords 1 Level 15. 5 feet the 48th Mile Post.

At 33 Cords 2 Levels 5 feet the 47th Mile Post.

At5h30mP.M. tB = 1.5 Longer

Thermometer 72° *D= 5 Shorter

Since lOh A. M. measured 35 Cords.

Measured in all this day 35 Cords. 348

28 At 8h 30m A. M. iB = 2 Longer

Thermometer 54° <D = 5 Shorter

At6hP.M. t B = 1 Longer

Thermometer 61.5° <D - 3 Shorter Since 8h 30m A. M. measured 33 Cords,

Measured in all this day 33 Cords.

29 _

30 At7hA.M. tB = 12. 5) Longer

Thermometer 60° *D = 6. 5»

At 9 Cords 3 Levels 2. 5 feet the 45th Mile Post.

At2hP.M. tB = 7» Longer

Thermometer 76° ‘D = 4’

Since 7h A. M. measured 28 Cords.

At 31 Cords 3 Levels 9. 5 feet the 44th Mile Post.

At6hP.M. tB = 7/ Longer

Thermometer 73° <D = 4> Since 2h P.M. measured 9 Cords.

Measured in all this day 37 Cords.

The last 11 Cords passed through a Swamp near the Head of the River Choptank:

The Water near two feet deep.

May

1 Sun. At Mr. West's, late Mr. Robinson's.

2 At 8h 30m A. M. tB = 6 Longer

Thermometer 54° *D = 1 Shorter

At 16 Cords 3 Levels 19 feet the 43rd Mile Post.

At 6h 30m P. M. tB = 7) Longer

Thermometer 56° <D = 2’ Since 8h 30m A. M. measured 32 Cords.

Measured in all this day 32 Cords.

N. B. The last 3 or 4 Cords passed across a Mill Pond in Choptank which I did not

attend: The Water about 4 feet deep. 349

At lOh A. M. tB = 7.5) Long^

Thermometer 61° »D = 4 '

At 6 Cords 7 Levels 13 feet the 42nd Mile Post.

At3hP.M. iB = 2> Longer

Thermometer 82° < D = 0>

Since lOh A.M. measured 24 Cords.

At 6h 15m P. M. tB= 5.5) Longer

Thermometer 75?5 <D = 2 »

Since 3h P.M. measured 9 Cords.

Measured in all this day 33 Cords.

Note: There appears to be an error of one chain in the former measurement: For
the 43rd Mile Post at 3 Levels 19 feet

Common difference about _ + 8

the 42nd should have been at 4 Levels 7 feet
but was at 7_ 13

Difference - 66 ft. = 1 chain = 3 Levels 6 feet That the Mile between the 42nd and 43rd is too great.

205

1768

May

4 At llh 30m A. M. .B s 7.5) Long^

Thermometer 79° Id = 4 I Thunder storm all the morning.

At 17 Cords 8 Levels 9 feet the 40th Mile Post.

Measured in all this day 19 Cords.

This passed the South Bank of the Main Branch of the Choptank one Level. This Branch was about
4 Levels wide and 3. 5 feet deep.

5 At 8h A. M. t B - 5.5/ Long.

Thermometer 70?5 *D = 6 >

At 20 Cords 8 Levels 17 feet the 39th Mile Post.

At 2h P.M. iB = 2 | Longer

Thermometer 86° <D = 0 >

Since 8h A. M. measured 22 Cords.

At 5h 30m P. M. B = 6 Longer

Thermometer 72° D = 3

Since 2h P.M. Measured 11 Cords.

Measured in all this day 33 Cords.

350

At 9h 30m A. M. iB = lli Long.

Thermometer 66° J D = 3 >

At 9 Cords 9 Levels 11 feet the 38th Mile Post.

At 4h P. M. iB = 8 ) Longer

Thermometer 63° *D= 7.5'

Since 9h 30m A. M. measured 27 Cords.

At 31 Cords 10 Levels 5 feet the 37th Mile Post:

After 4h P. M. we measured 6 Cords.

Measured in all this day 33 Cords.

At 8h A. M. )B = 9.5» Longer

Thermometer 60° /D = 9 \

At 20 Cords 10 Levels 19. 5 feet, the 36th Mile Post.

At3hP.M. tB = 3.5* Long.

Thermometer 74° «D = 3 i

Since 8h A. M. measured 34 Cords.

Measured in all this day 34 Cords.

8 Sun. In the Golden Grove.

At 7h 30m A.M. tB = 3 Longer

Thermometer 63° 'D = 0

At 8 Cords 11 Levels 13. 5 feet the 35th Mile Pest.

31 Cords 0 Levels 8 feet the 34th Mile Post.

At 4h 30m P.M. iB = 1.5 Shorter

Thermometer = 85° <D - 8

Since 7h 30m A. M. measured 44 Cords.

Measured in all this day 44 Cords.

10 At 8h 30m A. M. tB = 3 Longer

Thermometer 61° <D = 2.5 Shorter

At 9 Cords 1 Level 2. 5 feet the 33rd Mile Post.

At 7h P. M. tB = 0

Thermometer 68° <D = 1 Longer

Since 8h 30m measured 31 Cords.

Measured in all this day 31 Cords.

N. B. Corrected the Ends of the Levels, which were a little out of Perpendicular. 351

At 9h 15m A. M. iB = 7. 5 Longer

Thermometer 70° *D = 3. 5

Rain in the Night and Morning.

At 6h 30m P.M. iB = 3 Long,

Thermometer 72° » D * 3

Since 9h 30m A. M. measured 44 Cords.

Measured in all this day 44 Cords.

At 7h A. M. tB - 12 Longer

Thermometer 54? 5 <D = 11
Rain in the Night.

At2hP.M. tB = 2 j Longer

Thermometer 67° *D = 1>

Since 7h A.M. measured 22 Cords.

At 44 Cords 5 Levels 2 feet the 28th Mile Post.

At 6h 30m P.M. tB = 1.5 Long.

Thermometer 68° *D = 0

Since 2h P.M. Measured 23 Cords.

Measured in all this day 45 Cords.

206

1768

May

13 At 8h 30m A. M. (B= 8/ Longer

Thermometer 68° /D = 2J

At 21 Cords 5 Levels 17 feet the 27th Mile Post.
At 3h P. M. |B= 0

Thermometer 75° /D = 2.5 Shorter

Since 8h 30m A. M. Measured 25 Cords.

After 3h P.M. measured 8 Cords.

Measured in all this day 33 Cords.

14 At lOh 30m A. M. jB = 4 Longer

Thermometer 66° jD = 10.5

At 3h P. M. |B= 8/ Longer

Thermometer 74?5 /D = 6 }

Since lOh 30m measured 22 Cords.

Measured in all this day 22 Cords.

15 Sun. At Kemuel Godwin's.

16 At 7h 30m A. M. I B = 10 j Long,

Thermometer 57° / D = 9 \

At 10 Cords 7 Levels 9 feet, the 25th Mile Post.

At 3h 15m P. M. (B = 0 )

Thermometer 81° / D * 2( Shorter

Since 7h 30m A. M. Measured 32 Cords.

At 32 Cords 8 Levels 9. 5 feet the 24th Mile Post.

After 3h 30m measured 12 Cords.

Measured in all this day 44 Cords.

At 8h 30m A. M. \B = 7 1 Longer

Thermometer 66° /D = 5j

At 10 Cords 9 Levels 3. 5 feet the hole where the 23rd Mile Post stood; the Post

Lying by it.

At 3h P. M. | B = 4.5/ Shorter. Since 8h 30m A. M. Measured 32 Cords.

Thermometer 87° / D = 4 ^

At 32 Cords 9 Levels 15 feet, the 22nd Mile Post.

After 3h P.M. measured 12 Cords.

Measured in all this day 44 Cords.

18 At 8h 30m A. M. \ B = 5.5/ Long,

Thermometer 67° / D = 3 (

At 10 Cords 10 Levels 7. 5 feet the 21st Mile Post.

At lh P.M. j B = 10 i Longer, measured my self

Thermometer 90° j D = 4 J

Since 8h 30m A. M. measured 12 Cords.

The last 4 Cords passed through Marshy-Hope; The Water 4 and some places 5 feet
deep: this I did not attend.

Measured in all this day 12 Cords.

NOTE: The Brass Standard was wet, nearly all the time coming through

the water.

19

At 9h 30m A. M. 1

Thermometer 69° j

0 w

M II

a A

Long.

At 3h P. M. J

i B =

6 1

Long.

Thermometer 86° i

f D =

1.5$

■' y '

Since 9h 30m A. M. Measured 22 Cords.

Measured in all this day 22 Cords.

20 At 8h A. M. \ B = 10 / Long,

Thermometer 69° ) D = 7 (

Great dews for 4 morryings past.

At 20 Cords 11 Levels 9. 5 feet the 19th Mile Post.
At 3h P. M. \B= 3/ Longer

Thermometer 93° / D = 1}

Since 8h A. M. Measured 23 Cords.

After 3h P.M. Measured 14 Cords At 6h P. M.
Measured in all this day 37 Cords.

352

353

207

1768

May

21 At 9h A. M. \B = 5/ Longer

Thermometer 73° /D = 3\ Great dew.

At 6 Cords and four feet, the 18th Mile Post.

At 4h P. M. \b= 2/ Longer

Thermometer 86 ° ]d = 3 j Shorter

Since 9h A. M. measured 30 Cords.

Measured in all this day 30 Cords.

22 Sun. At Mr. Brown's. ,

23 Rain.

24 At 7h A. M. Jb = 19 [ Longer

Thermometer 50° Jd = 16 |

At 3h P. M. JB = 11 | Longer

Thermometer 75° |d = 10 f

Since 9h A, M. measured 40 Cords.

At 42 Cords 1 Level 13 feet the 15th Mile Post.

After 3h P.M. Measured 15 Cords.

Measured in all this day 55 Cords. 354

At 9h 30m A. M. \B = 16) Longer

Thermometer 59° /D = 12 \

At 31 Cords 2 Levels 7. 5 feet, the Hole or place where the 13th Mile Post stood.

At 4h P. M. \B = 19 / Long.

Thermometer 56° /D=15\

Since 9h 30m A. M. Measured 33 Cords.

Measured in all this day 33 Cords.

Rain last Night and this Morning: Passed this Morning half a mile
through water about 18 Inches deep.

At 9h 30m A. M. \b= 21( Long.

Thermometer 58° /D s 17 J

At 20 Cords 2 Levels 12. 5 feet, the place where the
12 th Mile Post stood. And at 42 Cords 2 Levels 19. 5 feet
Ditto, the 11th Mile Post.

At 5h 30m P.M. Jb= 21( Long.

Thermometer 53° /D = 15}

Since 9h 30m A. M. Measured 44 Cords.

Measured in all this day 44 Cords.

Rain last night and part of this day; the
Levels continually wet.

At 8 h A. M. |B = 11 j Long,

Thermometer 65° /D = 7(

9 Cords 8 Levels 8 . 5 feet

At 19 Cords 9 Levels 4 feet The Points from which we laid off the

42 Cords 2 Levels 16 feet Offsets (in 1764) for the true Tangent Line.

At 20 Cords 3 Levels 4 feet the 10 th Mile Post.

At 3h 15m P.M. \b = 8 / Long.

Thermometer 79° /D = 6 }

Since 8 h A. M. Measured 33 Cords.

At 42 Cords 3 Levels 12 feet the 9th Mile Post.

After 3h 15m measured 22 Cords. (At 7h P.M. finished).

Measured in all this day 55 Cords.

Dry weather. 355

29 Sun. At Mr. John Twiford's on the ^anks of the River Nanticoke.

30 _

31 At 8 h 15m A. M. lB = l/ Long,

Thermometer 79° (D = 0}

At 9 Cords 3 Levels 19. 5 feet, the 8 th Mile Post,

At 3h 30m P. M. \ B = 4 j Shorter

Thermometer 90° ] D = 8 \

Since 8 h 15m A. M. Measured 31 Cords 4 Levels which
reached to the River Nanticoke; High Water,

Measured in all this day 31 Cords and 4 Levels *

N. B. Very dry weather for 3 days past: The Levels
did not pass through any water this day.

At 31 Cords 4 Levels 13. 5 feet, the 7th Mile Post.

This was found by squaring off to

the Post in our second Line, for it was removed out

of this Line at Right Angles in 1764.

208

1768

June

1

2 Began at the 6th Mile Post at 8h A. M. (B - 7. 5} Long.

|D = 0 J Thermometer 84°

At 2h 30m P. M. B = 7 Long.

Thermometer 74° D = 1

Since 8h A. M. measured 25 Cords.

After 2h 30m P. M. Measured 19 Cords.

Measured in all this day 44 Cords.

At 9h A. M. jB-10.5) Long.

Thermometer 76° |d = 5 l

At 0 Cords 1 Level 3 feet, the 4th Mile Post.

At 3h P. M. \B= 2.5} Long.

Thermometer 85° /D = 0. 5J Short

Since 9h A. M. Measured 33 Cords.

At 44 Cords 1 Level 16 feet the second Mile Post.

After 3h P.M. Measured 22 Cords.

Measured in all this day 55 Cords.

At 6h 15m A. M. JB = 14 } Long.

Thermometer 64° (D = 7+j

AtlhP.M. \B = 2 } Longer than the Standard

Thermometer 82° /D = 2 \ Shorter

Since 6h 15m Measured 33 Cords 2 Levels 17. 5 feet.

Measured in all this day 33 Cords 2 Levels 17. 5 feet which reached the
Middle Point.

Note: This day we left a Mark in the ground (in a swamp) 12 Cords
before we came to the Middle Point; when we came to the 1st
Middle Point we measured back again to the Mark; and we fell
short of the said Mark about 4 Inches.

5 Sun. At Mr. Twiford's,

Began at the 6th Mile Post and measured Northward through the
Cripple of Nanticoke.

At 7h 30m A. M. jB = 8 } Long.

Thermometer 67° {D = 4 ^

At 2h P. M. |B - 5.5} Long.

Thermometer 77° |D = 0 J

Since 7h 30m A. M. we have measured 19 Cords 2 Levels which reached
to a Mark on the South Side of the River Nanticoke.

Passed over the River and began at the Point left off at on the

31st of May viz at 31 Cords 4 Levels; and measured three Levels South

and there placed a Mark: We then measured a Base from this

last Mark (westward) of 24 Levels; and there placed Mark; and

then took the Angles as by the Figure.

Here AB the River. AC = 24 Levels.

Angles taken with a Hadley's Quadrant
as by the Figure. This Quadrant had an Ivory
Arch, divided as Mr. Bird's but the makers
name was not upon it.

Hence the Breadth of the River AB = 31. 67 Levels,

Measured in all this day 19 Cords 5 Levels besides the distance
between the Marks placed near the Banks of the River.

N. B. Since March the 12th Inclusive. Each Cord has been

equal to 12 Levels. The Level B always beginning the Cord,

and D ending it; so that except the Cord lengthened or

shortened more than one-half a Level no error of 2 Levels could arise

which was never the case; the Cord was often daily proved, and when

down was not taken up till the Level D was brought to

its place.

One Man was constantly employed to stretch the Cord, who also
kept the Reckoning besides Mr. Dixon and myself; so that no
error of a Cord could arise: Even the Mile Posts were sufficient
for that purpose as the Lines had been measured so often before.

356

Figure

357

209

1768

June

9

Left Mr. Twiford's. Situated on the most Rural and delightful
Banks of River Nanticoke. Here is the most pleasing Contemplative
View I've ever seen in America; the River makes a turn from
the Southward to the Eastward nearly at Right Angles and not one House
to be seen on either side of the River, though the whole in
View for 4 Miles: But Nature's genuine produce of
Pine and Cedar on both sides its rural Banks, for
which Ships resort from all parts to supply distant
Climes destitute of so great a blessing.

10 At Dover.

11 At Mount Pleasant.

12 Sun. At Ditto.

13 At Newark,

14 Discharged all Hands.

16 At Brandywine.

20 At Philadelphia.

21 Informed the Commissioners we had finished the mensuration

of a Degree of Latitude for the Royal Society; and that we

were now ready for returning Home.

Were informed by the Reverend Mr. Peters and Mr. Chew, that a meeting
of the Commissioners of both Provinces was necessary
before we left the Continent; and that before this meeting, they desired
to have the Plan of the Lines Engraved.

26 Sun. Returned to the Forks of Brandywine.

29 At Philadelphia.

Moon Eclipsed

At 8h 48m by the Watch, the Moon entered the Cloud; the Eclipse

not begun. Clouds continued etc. 359

July

8 Compared the 5 feet brass Rod (which we used on measuring

the Lines for the Royal Society) with the brass Yard belonging
to the 6 foot Sector; and found it one Division and a half of
those divisions at the End of the Brass Rod (that is .015
of an Inch) shorter than the Yard in 5 feet. - Thermometer 70°; t wo
of them agreeing, one of which we used on the Line.

We compared the measures by taking the whole Yard and
two feet, and also by taking 2. 5 feet on the Yard twice,it always
by many trials appearing that the Rod is not 5 feet according to the Yard;
it wanting .015 of an Inch
_4

.060 in one Level
264 Levels in one Mile
240
360
120

15. 840 = Inches in a Mile difference between the
measures: therefore our measurements by the Levels should
be 15. 84 Inches in a Mile more than by the Chain Measure; that is;
the distance between the Mile Posts should be one Mile
and 15. 84 Inches.

N. B. We have marked the length of the Yard from one End of the Rod by making
a point between two scratches thus 1 * 1 on the Rod.

18 Acquainted Mr. Chew that Mr. Dawkins who had undertaken

(by an agreement with the Reverend Mr. Ewen, one of the Gentlemen Commissioners) to
Engrave a Plan of the Lines (and had about half finished it);
would not proceed farther in the work.

19 Mr. Smither engaged to finish the Engraving the said Plans
by an agreement with Mr. Chew.

August

16 Two Hundred copies of the Plans of the Lines Printed off. 360

210

Mr. Charles Mason

(Editorial Note: Certificate of Admission to membership in the American Philosophical Society.)
Mr. Charles Mason

is duly admitted a corresponding Member of the
American Society held at Philadelphia for
promoting useful knowledge. Dated 15 Day of
April AD 1768.

Signed by order of the Society
Cha. Thomson

Corresponding Secretary

1768

August

17

25

26
27

The Rev. Mr. Peters informed us there was a Meeting of the
Gentlemen Commissioners of both Provinces to be held at Newtown
on Chester River in Maryland, the 25th Instant; where we
were desired to attend.

Attended the Gentlemen Commissioners at New Town,
where our accounts were settled. Certificates given us
of the same: and the whole work of our part relating
to the Business we had been engaged in for the Honorable
Proprietors of Maryland and Pennsylvania, was entirely finished.
At Philadelphia.

September

8 Left Ditto and proceeded for New York.

9 At Ditto.

10 At Ditto.

11 At llh 30m A. M. went on Board the Halifax Packet Boat for

Falmouth. Thus ends my restless progress

in America.

C. Mason

(Undated An envelope addressed to Messrs. Mason and Dixon
in the handwriting of Thomas Penn.)

362

Mr. Charles Mason and Jeremiah
Dixon at the Prince of Wales’s Arms
the Corner of

Leicester Fields
London

WINDSOR
(Rubber Stamp)

Gentlemen:

I have received your letter and account and shall
be inlbwn on Thursday about three o'clock. I am by appointment to
dine with Mr. Wilmot Friday and would meet Mr. Hemessley an hour before dinner
there or if he will tell you what time will best suit him and you inform
me of it Thursday at three o'clock I will endeavour to make it suit me,
and will see Mr. Wilmot the same morning at the House of Lords, I am

Your very humble Servant
Thomas Penn

Hope House near Windsor 3^4

November 14, 1768

211

FIGURE 2lo

r

i

Ac

Ab

FIGURE 21b

I

FIGURE 23

FIGURE 24

19“

13yd. g6in.

FIGURE 107b

216

218

219

220

222

i

224

J

L

1° 11*25"26 according to Rumb
Meridian from the Middle Point

FIGURE 317

FIGURE 333a

/ \

/.«? %\

?g>

fto-i Hero A is allowed for figure for the adjustment of the quadrant

6 Lewe.s ljut j'by q near obieet

FIGURE 333b /£

/ n

In tAiE figure r‘is allowed for p near of the quQdrflnl

FIGURE 334 /

1 0 Levels

i fiere She adiuetmaM hut li’os is allowed the figure

7

228

APPENDIX

ENTRIES PRECEDING THE JOURNAL

Mason and Dixon's record of their survey actually
begins on page 25 of the manuscript Journal as it has
come down to us. The first 24 pages contain material
which is extraneous, incidental, or misplaced as follows:

Pages 1-4. Explanatory introduction added when the
manuscript was in possession of the Department of
State. Its contents are utilized in the first chapter of
the editorial Introduction.

Pages 5-12. Correspondence regarding the acquisition
of the manuscript by the Department of State:

Department of State.

Washington, November 2, 1876.
George W. Childs, Esquire,

Philadelphia, Pennsylvania.

Sir:

On September 3rd. a Mr. S. P. Mayberry addressed the
Secretary of the Interior from the Elm Avenue Hotel,
Philadelphia, stating that the original journal of the Com¬
missioners who located Mason and Dixon's line, giving a
full and complete account relative to the proceedings each
day, was on exhibition at the Centennial Exhibition, and
belonged to a gentleman in Halifax; and the writer sug¬
gested that the journal be bought, if possible.

The matter has been referred to me, and as I have no
acquaintance with the writer himself, and as it is not at all
likely that he can now be found near Philadelphia, I take
the liberty of addressing you, to ask whether you will oblige
me by causing the proper inquiries to be cautiously made—
probably in the Canadian Department, as the owner was
said to reside at Halifax, to ascertain whether such journal
actually exists, and if so, to find out, confidentially, whether
it can be purchased, and for what sum.

I may add that the funds at the control of this Depart¬
ment for any such purpose are really small, and that no
considerable price could be paid; at the same time it is be¬
lieved that the notes of survey are valuable and desirable
to the Government.

am, Sir,

Your obedient servant,
Hamilton Fish.

Office of the Public Ledger.
Philadelphia, February 12, 1877

Mr dear Mr. Fish:

I enclose a letter my friend Mr. Dreer has just received
in regard to the Mason & Dixon matter. Mr. D. says it is
the best copy in existence and has matter connected with it
that the others have not.

The owner has no idea who wants it, nor are we in any
way committed.

With high esteem,
very truly your friend
Geo. W. Childs

Hon. Hamilton Fish

Department of State.

Washington, February 17th, 1877.

George W. Childs, Esq.

Philadelphia, Pa.

My dear Sir:

I have to acknowledge the receipt of your note of the 12th
instant enclosing a letter to Mr. Dreer from the owner of
the manuscripts relating to the Mason and Dixon line.

I will take advantage of the interest you have shown in
securing the manuscripts to this Department; by requesting
you to conclude the purchase of them at the price named
by their owner, five hundred dollars in gold; and I will
thank you to inform me when and by what means I shall
remit a draft for the same.

I return herewith Mr. James' letter.

I am, my dear Sir,

Your obedient servant.
Hamilton Fish.

Halifax, Nova Scotia
Provincial Museum.
Feb. 26, / 77.

Secy. Hamilton Fish
Sir:

We have just received a letter from Mr. Dreer of Phili. in
which he says that you desired him to request (Judge)
A. James to send the Mason & Dixon Journal to your
address, and that you would remit to him a Draft for Five
Hundred Dollars in Gold.

I am instructed accordingly by Judge James to forward
to you the said Journal.

I have the honor to be
Your obedient servant,

D. Honeyman

Judge

Alexander James

(of the Supreme Court of Nova Scotia)

P.S. Some of the members of the Nova Scotia Govern¬
ment have a wish to retain it in N.S. but the proper place
for it is in the Archives of the Government of the United
States.

D. H.

229

230

THE JOURNAL OF CHARLES MASON AND JEREMIAH DIXON

Halifax, Nova Scotia The Eclipse of the Moon ended in the Forks of the Brandy-
March 8, 1877 wine the 17th of March 1764 at 8h 04m 10s by the watch.

Hon. Secretary
Hamilton Fish

State Department, Washington.

Sir:

I forwarded to you as instructed by Mr. Dreer of Phila¬
delphia a registered Package containing the Mason &
Dixon Journal. As I am responsible to Judge James, the
owner of the said Journal, for the Journal or its value $500
(Five Hundred Dollars in Gold) you will favor me by re¬
mitting to me the cheque for the above amount in terms of
the agreement with Mr. Dreer. It was committed to my care
as the Representative of Nova Scotia in the Canadian De¬
partment of the Centennial Exhibition and exhibited in our
Department where it came to Mr. Dreer's notice.

I have the honor to be
Your obedient servant
D. Honeyman

Address

Rev. Dr. David Honeyman

Director of the Provincial Museum,

Halifax, Nova Scotia.

If you wish any information regarding y6ut correspond¬
ent, apply to my personal friends Dr. F. V, Hayden & Prof.
Baird.

Department of State.
Washington, D.C.
March 8th, 1877.

George W. Childs, Esq.

Philadelphia, Pa.

Sir:

Referring to previous correspondence on the subject, I
have to enclose the Disbursing Clerk’s com check, No. 1483,
for $500, in payment of the original copy of the Field notes
of the survey of Mason & Dixon line; purchased of Dr.
Honeyman & also a voucher therefor, which I will thank
you to have signed by him and returned to this Department
at your earliest convenience.

I am, Sir, Your obedient servant.
Hamilton Fish.

Pages 13-16. Rough notes of observations, not printed
here because they appear in more finished style in the
Journal as indicated here:

P. 13. Observations reported as of 20 and 21 December,

m3.

P. 14. Observations reported as of 30 and 31 December,
1763, and 1 and 2 January, 1764.

P. 15. Observations reported as of 28, 29, and 30 De¬
cember, 1763.

P. 16. Observations reported as of 25 and 27 December,

1763.

Page 17 is blank except for the word “London.”

Pages 18-18a: Eclipse of the Moon, March, 1764:

Equal Altitudes of Regulus by the watch thus

8h

58m

46s

lOh

27m

30s (very dubious)

9h

01m

16s

lOh

29m

41s

9h

04m

05s

lOh

32m

09s

Hence Regulus passed the Meridian
by the watch 9h 45m 28s

Right Ascension of Regulus 9h 55m 48s

Watch slow for Sidereal Time Oh 10m 20s

Note: Air was very clear and eclipse observed with a mag¬
nifying power of about 50. The earth’s shadow on the
disk was the best defined I ever saw. The watch
moved very regular Sidereal Time.

19h

30m

57s

19h

30m

55s

19h

30m

56s

(Mean)

9h

45m

28s

Regulus passed according to the watch

9h

55m

48s

Right ascension of Regulus

Oh

10m

20s

Watch slow for Sidereal Time

8h

04m

10s

Eclipse of the Moon ended

8h

14m

30s

Right Ascension of the Mid Heaven at
time of Eclipse

23h

31m

27s

Right Ascension of the Sun

8h

23m

03s

Apparent time. Evening Estimate

lh

36m

40s

At Paris, morning of 18th

5h

13m

37s

Difference, Meridian at Paris by Estimate

23h

52m

31s

Right Ascension of Sun at the End of the
Eclipse seen at Brandywine

8h

14m

30s

Right Ascension of Mid-Heaven

8h

28m

59s

Apparent Time precisely

lh

36m

40s

At Paris

5h

14m

41s

Time Difference from Paris

Pages 19-20. Observations made in 1764:

This we finished the 20th of March, when we began to
run a Visto in the Meridian Southward. We measured the
horizontal distance twice over, dividing the distance into
five parts and any part that there was the least doubt of an
error we measured a third time; and the result was that
two measurements differed not quite three yards. All the
Hills were measured with levels having Plummets to shew
when they were Horizontal.—The Reckoning kept by each
of us and a Surveyor all separate. We have finished a
(Datum) for Running the Western Boundary; and have
set up a post Marked West.

Received your letter of Thursday and we shall exert our
utmost endeavor to completely answer its contents. The
beginning of the winter was very favourable for observa¬
tions, but the Spring has been almost entirely cloudy.—
Your Instrument, the Sector, Returns to itself with such
accuracy that we hope our journal will bear the nicest ex¬
amination of any Practical Astronomer.

The Latitude of the Southernmost point of the City of
Philadelphia; from the mean of 32 observations the extreme
of which differed only 3."5 is 39°56'29/T North. At this
point we settled the Zenith Distances of 8 stars from the
Mean of 52 observations. On the (blank) of January we
left Philadelphia and Set up the Sector in the Forks of

ENTRIES PRECEDING THE JOURNAL

231

Brandywine (31 miles west) where we made about the

same number of observations of the (stars).

Page 21. Observations reported in 1763 but of dubious
dating as Mason and Dixon did not arrive in Phila¬
delphia until late that year.

81 Miles

81 miles 74 chains 25 links accord¬
ing to the Book = CA the Tan¬
gent when the radius was contin¬
ued, 5 -chains 25 links West of the
12 miles from Newcastle

firmly in the earth a square white post marked TP and after
we had fixed the same we took the bearings and distances
of several trees, etc. to know if it wanted to be moved; next
proceeded to go back and mark off the offsets from each
5 mile post agreeable to calculation.

Figures 21a and b

Page 22. Miscellaneous notes dated between 1762 and
1767:

From the Meridian first run they were to lay off an angle
of 3°32'5" westerly by a meeting of the Commissioners held
at New Castle the 30th of April 1762. The 25th of May
1762 the Surveyors began at Midpoint and ended Sept. 9th

1762, when they say from the 81 Milepost they continued
the line 60 chains, where they placed a squared white post,
and then continued it 14 chains 65 links to another white
oak post set in the intersection of the said line and 12 mile
line or radius run from the center of Newcastle last winter,
the said post being 33 chains 76 links Eastward of the post
fixed at the extremity of the radius. They afterwards by
Lord Baltimores large Theodolite took the angle included
between the now finished line and the 12 mile line run from
the center of New Castle last winter and judged the same
to be somewhat more than 90°26' which excess could not be
exactly determined by the said Instrument.

On the 17th September 1762, The Commissioners gave the
surveyors the following instructions. You are to go to the
post marked Middle point and set off an angle from the
line last run Northwesterly of 16'40". Agreeable to this
they met at the Middle point 18th September 1762 and pro¬
ceeded to run a third line which they ended the 19th August

1763, which ran 5 chains 25 links west of the Periphery of
the circle, see the other side of this paper.

Note: In April 1767 William Lukins (Surveyor General of
the Province of Pennsylvania) told me that our
statute yard was the thickness of a piece of Parch¬
ment shorter than theirs, with which they measured
the Tangent Line.

Pages 23-24 contain only diagrams which are repro¬
duced in original or transcribed from elsewhere in
the present volume (figs. 5, 23, 24).